Matching Items MCQs for Sub-Topics of Topic 8: Trigonometry
Introduction to Trigonometry and Basic Ratios (Right Triangle Trigonometry)
Question 1. Match the trigonometric ratio with its definition in a right triangle for an acute angle $\theta$:
(i) Sine
(ii) Cosine
(iii) Tangent
(iv) Cotangent
(a) $\frac{\text{Adjacent side}}{\text{Opposite side}}$
(b) $\frac{\text{Opposite side}}{\text{Hypotenuse}}$
(c) $\frac{\text{Adjacent side}}{\text{Hypotenuse}}$
(d) $\frac{\text{Opposite side}}{\text{Adjacent side}}$
Answer:
Question 2. Match the reciprocal trigonometric ratios:
(i) $\sin \theta$
(ii) $\cos \theta$
(iii) $\tan \theta$
(iv) $\sec \theta$
(a) $\cot \theta$
(b) $\text{cosec } \theta$
(c) $\tan \theta$
(d) $\sec \theta$
Answer:
Question 3. In a right triangle ABC, right-angled at B, match the sides with the angle A:
(i) Side opposite to angle A
(ii) Side adjacent to angle A
(iii) Side opposite to angle B
(iv) Side opposite to angle C
(a) BC
(b) AC (Hypotenuse)
(c) AB
(d) Cannot be determined without more information
Answer:
Question 4. Match the given trigonometric values with the approximate decimal values for an acute angle $\theta$:
(i) $\sin 30^\circ$
(ii) $\cos 45^\circ$
(iii) $\tan 60^\circ$
(iv) $\sin 90^\circ$
(a) 1
(b) $\approx 0.707$
(c) 0.5
(d) $\approx 1.732$
Answer:
Question 5. Match the relationships between trigonometric ratios:
(i) $\tan \theta$
(ii) $\cot \theta$
(iii) $\sec \theta$
(iv) $\text{cosec } \theta$
(a) $\frac{1}{\cos \theta}$
(b) $\frac{\cos \theta}{\sin \theta}$
(c) $\frac{1}{\sin \theta}$
(d) $\frac{\sin \theta}{\cos \theta}$
Answer:
Trigonometric Ratios of Special Angles and Complementary Angles
Question 1. Match the special angles with their sine values:
(i) $0^\circ$
(ii) $30^\circ$
(iii) $45^\circ$
(iv) $60^\circ$
(a) $\frac{\sqrt{3}}{2}$
(b) $\frac{1}{\sqrt{2}}$
(c) $0$
(d) $\frac{1}{2}$
Answer:
Question 2. Match the special angles with their tangent values:
(i) $0^\circ$
(ii) $30^\circ$
(iii) $45^\circ$
(iv) $60^\circ$
(a) $\sqrt{3}$
(b) $\frac{1}{\sqrt{3}}$
(c) 1
(d) 0
Answer:
Question 3. Match the complementary angle relationships (where A is an acute angle):
(i) $\sin (90^\circ - A)$
(ii) $\cos (90^\circ - A)$
(iii) $\tan (90^\circ - A)$
(iv) $\sec (90^\circ - A)$
(a) $\text{cosec } A$
(b) $\cos A$
(c) $\sin A$
(d) $\cot A$
Answer:
Question 4. Evaluate the expressions involving special angles:
(i) $\sin 30^\circ + \cos 60^\circ$
(ii) $2 \tan 45^\circ$
(iii) $\sin^2 45^\circ + \cos^2 45^\circ$
(iv) $\sec 60^\circ$
(a) 1
(b) 2
(c) 1
(d) 2
Answer:
Question 5. Match the pairs that sum up to 1 using complementary angle properties:
(i) $\sin^2 25^\circ$
(ii) $\tan 10^\circ$
(iii) $\sec 40^\circ$
(iv) $\sin 10^\circ$
(a) $\cos 80^\circ$
(b) $\cos^2 65^\circ$
(c) $\text{cosec } 50^\circ$
(d) $\cot 80^\circ$
Answer:
Question 6. Match the angles with their cosine values:
(i) $0^\circ$
(ii) $30^\circ$
(iii) $45^\circ$
(iv) $60^\circ$
(a) $\frac{1}{2}$
(b) $\frac{1}{\sqrt{2}}$
(c) $\frac{\sqrt{3}}{2}$
(d) $1$
Answer:
Fundamental Trigonometric Identities
Question 1. Match the Pythagorean identities with their equivalent forms:
(i) $\sin^2 \theta + \cos^2 \theta$
(ii) $\sec^2 \theta - \tan^2 \theta$
(iii) $\text{cosec}^2 \theta - \cot^2 \theta$
(iv) $1 + \tan^2 \theta$
(a) 1
(b) $\text{cosec}^2 \theta$
(c) 1
(d) $\sec^2 \theta$
Answer:
Question 2. Match the quotient and reciprocal identities:
(i) $\frac{\sin \theta}{\cos \theta}$
(ii) $\frac{1}{\sin \theta}$
(iii) $\frac{\cos \theta}{\sin \theta}$
(iv) $\frac{1}{\cos \theta}$
(a) $\cot \theta$
(b) $\sec \theta$
(c) $\tan \theta$
(d) $\text{cosec } \theta$
Answer:
Question 3. Simplify the following expressions using fundamental identities:
(i) $\sin \theta \cdot \text{cosec } \theta$
(ii) $\cos \theta \cdot \tan \theta$
(iii) $(1 - \sin^2 \theta)$
(iv) $\sec^2 \theta - 1$
(a) $\tan^2 \theta$
(b) $\cos^2 \theta$
(c) $\sin \theta$
(d) 1
Answer:
Question 4. Match the equivalent expressions:
(i) $\frac{1 - \cos^2 A}{1 - \sin^2 A}$
(ii) $\frac{1}{\sec \theta - \tan \theta}$
(iii) $\sin^4 \theta + \cos^4 \theta$
(iv) $\frac{1 + \tan^2 \theta}{1 + \cot^2 \theta}$
(a) $1 - 2 \sin^2 \theta \cos^2 \theta$
(b) $\sec \theta + \tan \theta$
(c) $\tan^2 A$
(d) $\tan^2 \theta$
Answer:
Question 5. Match the identities with their simplified forms:
(i) $\sin^2 \theta \cot^2 \theta$
(ii) $\cos^2 \theta \tan^2 \theta$
(iii) $(\sec \theta + \tan \theta)(\sec \theta - \tan \theta)$
(iv) $(\text{cosec } \theta + \cot \theta)(\text{cosec } \theta - \cot \theta)$
(a) $\sin^2 \theta$
(b) 1
(c) 1
(d) $\cos^2 \theta$
Answer:
Angle Measurement: Degrees and Radians
Question 1. Match the angle measures in degrees with their equivalent radian measures:
(i) $30^\circ$
(ii) $45^\circ$
(iii) $60^\circ$
(iv) $90^\circ$
(a) $\frac{\pi}{4}$
(b) $\frac{\pi}{2}$
(c) $\frac{\pi}{6}$
(d) $\frac{\pi}{3}$
Answer:
Question 2. Match the radian measures with their equivalent degree measures:
(i) $\pi$
(ii) $2\pi$
(iii) $\frac{3\pi}{4}$
(iv) $\frac{5\pi}{6}$
(a) $360^\circ$
(b) $135^\circ$
(c) $150^\circ$
(d) $180^\circ$
Answer:
Question 3. Match the formulas related to arc length and sector area:
(i) Arc Length ($l$)
(ii) Area of Sector ($A$)
(iii) Central Angle ($\theta$ in radians)
(iv) Radius ($r$)
(a) $\frac{l}{r}$
(b) $r\theta$
(c) $\frac{2A}{l}$
(d) $\frac{1}{2} r^2 \theta$
Answer:
Question 4. Match the conversions between degrees and radians:
(i) $1^\circ$ to radians
(ii) 1 radian to degrees
(iii) $180^\circ$ to radians
(iv) $\pi$ radians to degrees
(a) $\pi/180$
(b) $180/\pi$
(c) $180^\circ$
(d) $\pi$
Answer:
Question 5. Given a circle with radius $7\ \text{cm}$, match the central angles with the corresponding arc lengths (Use $\pi = \frac{22}{7}$):
(i) $\frac{\pi}{2}$ radians
(ii) $\pi$ radians
(iii) $60^\circ$
(iv) $120^\circ$
(a) 22 cm
(b) 11 cm
(c) $\frac{44}{3}$ cm
(d) 44 cm
Answer:
Trigonometric Functions of a Real Number (Unit Circle Approach)
Question 1. Match the angle measures with the coordinates of the point on the unit circle:
(i) $0$ radians
(ii) $\frac{\pi}{2}$ radians
(iii) $\pi$ radians
(iv) $\frac{3\pi}{2}$ radians
(a) $(0, 1)$
(b) $(-1, 0)$
(c) $(1, 0)$
(d) $(0, -1)$
Answer:
Question 2. Match the angle ranges with the quadrant they lie in:
(i) $0 < \theta < \frac{\pi}{2}$
(ii) $\frac{\pi}{2} < \theta < \pi$
(iii) $\pi < \theta < \frac{3\pi}{2}$
(iv) $\frac{3\pi}{2} < \theta < 2\pi$
(a) Quadrant IV
(b) Quadrant II
(c) Quadrant I
(d) Quadrant III
Answer:
Question 3. Match the trigonometric functions with their principal period:
(i) $\sin x$
(ii) $\cos x$
(iii) $\tan x$
(iv) $\cot x$
(a) $\pi$
(b) $2\pi$
(c) $2\pi$
(d) $\pi$
Answer:
Question 4. Match the values of trigonometric functions for specific angles:
(i) $\sin \pi$
(ii) $\cos \frac{\pi}{2}$
(iii) $\tan \pi$
(iv) $\sin \frac{3\pi}{2}$
(a) 0
(b) -1
(c) 0
(d) 0
Answer:
Question 5. Match the quadrant with the sign of the trigonometric function:
(i) Quadrant II
(ii) Quadrant III
(iii) Quadrant IV
(iv) Quadrant I
(a) $\cos \theta > 0, \sin \theta < 0$
(b) $\sin \theta > 0, \cos \theta < 0$
(c) $\sin \theta > 0, \cos \theta > 0$
(d) $\sin \theta < 0, \cos \theta < 0$
Answer:
Question 6. Match the trigonometric functions with their range:
(i) $\sin x$
(ii) $\tan x$
(iii) $\sec x$
(iv) $\cot x$
(a) $\mathbb{R} - (-1, 1)$
(b) $\mathbb{R}$
(c) $[-1, 1]$
(d) $\mathbb{R}$
Answer:
Graphs of Trigonometric Functions
Question 1. Match the trigonometric function with a point on its graph:
(i) $y = \sin x$
(ii) $y = \cos x$
(iii) $y = \tan x$
(iv) $y = \cot x$
(a) $(\frac{\pi}{4}, 1)$
(b) $(0, 0)$
(c) $(\frac{\pi}{2}, 0)$
(d) $(\frac{\pi}{2}, 0)$
Answer:
Question 2. Match the function with its amplitude:
(i) $y = \sin x$
(ii) $y = 3 \cos x$
(iii) $y = -2 \sin x$
(iv) $y = \tan x$
(a) Not applicable
(b) 1
(c) 3
(d) 2
Answer:
Question 3. Match the function with its principal period:
(i) $y = \cos x$
(ii) $y = \tan x$
(iii) $y = \sin (2x)$
(iv) $y = \cos (x/2)$
(a) $4\pi$
(b) $\pi$
(c) $2\pi$
(d) $\pi$
Answer:
Question 4. Match the function with the location of its vertical asymptotes ($n \in \mathbb{Z}$):
(i) $y = \tan x$
(ii) $y = \cot x$
(iii) $y = \sec x$
(iv) $y = \text{cosec } x$
(a) $x = n\pi$
(b) $x = (2n+1)\frac{\pi}{2}$
(c) $x = n\pi$
(d) $x = (2n+1)\frac{\pi}{2}$
Answer:
Question 5. Match the range of the function:
(i) $y = 2 \sin x$
(ii) $y = - \cos x$
(iii) $y = 1 + \sin x$
(iv) $y = \sec x$
(a) $[-1, 1]$
(b) $[1, 3]$
(c) $[-2, 2]$
(d) $(-\infty, -1] \cup [1, \infty)$
Answer:
Trigonometric Identities: Compound and Multiple Angles
Question 1. Match the identity with its correct expansion:
(i) $\sin(A-B)$
(ii) $\cos(A+B)$
(iii) $\tan(A+B)$
(iv) $\sin 2A$
(a) $\sin A \cos B - \cos A \sin B$
(b) $2 \sin A \cos A$
(c) $\frac{\tan A + \tan B}{1 - \tan A \tan B}$
(d) $\cos A \cos B - \sin A \sin B$
Answer:
Question 2. Match the identity with its equivalent form:
(i) $\cos 2A$
(ii) $\cos 2A$
(iii) $\cos 2A$
(iv) $\tan 2A$
(a) $2 \cos^2 A - 1$
(b) $\frac{1 - \tan^2 A}{1 + \tan^2 A}$
(c) $\cos^2 A - \sin^2 A$
(d) $\frac{2 \tan A}{1 - \tan^2 A}$
Answer:
Question 3. Match the values of trigonometric functions for compound angles:
(i) $\sin 75^\circ$
(ii) $\cos 15^\circ$
(iii) $\tan 15^\circ$
(iv) $\cos 75^\circ$
(a) $\frac{\sqrt{3}-1}{2\sqrt{2}}$
(b) $2 - \sqrt{3}$
(c) $\frac{\sqrt{3}+1}{2\sqrt{2}}$
(d) $\frac{\sqrt{3}+1}{2\sqrt{2}}$
Answer:
Question 4. Match the identities involving $1 \pm \cos 2\theta$:
(i) $1 + \cos 2\theta$
(ii) $1 - \cos 2\theta$
(iii) $\frac{1 + \cos 2\theta}{2}$
(iv) $\frac{1 - \cos 2\theta}{2}$
(a) $\sin^2 \theta$
(b) $2 \sin^2 \theta$
(c) $\cos^2 \theta$
(d) $2 \cos^2 \theta$
Answer:
Question 5. Match the identity with its correct expansion:
(i) $\tan(A-B)$
(ii) $\cos(A-B)$
(iii) $\sin(A+B)$
(iv) $\cos(A+B)$
(a) $\cos A \cos B + \sin A \sin B$
(b) $\sin A \cos B + \cos A \sin B$
(c) $\cos A \cos B - \sin A \sin B$
(d) $\frac{\tan A - \tan B}{1 + \tan A \tan B}$
Answer:
Question 6. Match the multiple angle identities:
(i) $\sin 3A$
(ii) $\cos 3A$
(iii) $\tan 3A$
(iv) $\frac{1 - \tan^2 A}{1 + \tan^2 A}$
(a) $\frac{3 \tan A - \tan^3 A}{1 - 3 \tan^2 A}$
(b) $3 \sin A - 4 \sin^3 A$
(c) $\cos 2A$
(d) $4 \cos^3 A - 3 \cos A$
Answer:
Trigonometric Transformations: Product-to-Sum and Sum-to-Product
Question 1. Match the product-to-sum formulas:
(i) $2 \sin A \cos B$
(ii) $2 \cos A \sin B$
(iii) $2 \cos A \cos B$
(iv) $2 \sin A \sin B$
(a) $\cos(A+B) + \cos(A-B)$
(b) $\sin(A+B) - \sin(A-B)$
(c) $\cos(A-B) - \cos(A+B)$
(d) $\sin(A+B) + \sin(A-B)$
Answer:
Question 2. Match the sum-to-product formulas:
(i) $\sin C + \sin D$
(ii) $\sin C - \sin D$
(iii) $\cos C + \cos D$
(iv) $\cos C - \cos D$
(a) $2 \cos \left(\frac{C+D}{2}\right) \cos \left(\frac{C-D}{2}\right)$
(b) $2 \sin \left(\frac{C+D}{2}\right) \cos \left(\frac{C-D}{2}\right)$
(c) $2 \cos \left(\frac{C+D}{2}\right) \sin \left(\frac{C-D}{2}\right)$
(d) $-2 \sin \left(\frac{C+D}{2}\right) \sin \left(\frac{C-D}{2}\right)$
Answer:
Question 3. Simplify the following expressions using sum-to-product or product-to-sum formulas:
(i) $\sin 5\theta + \sin 3\theta$
(ii) $\cos 4x - \cos 2x$
(iii) $2 \sin 4A \cos A$
(iv) $2 \cos 3\theta \cos \theta$
(a) $\sin 5A + \sin 3A$
(b) $\cos 4\theta + \cos 2\theta$
(c) $2 \sin 4\theta \cos \theta$
(d) $-2 \sin 3x \sin x$
Answer:
Question 4. Match the equivalent expressions (where defined):
(i) $\frac{\sin x + \sin y}{\cos x + \cos y}$
(ii) $\frac{\sin x - \sin y}{\cos x - \cos y}$
(iii) $\sin(A+B)\sin(A-B)$
(iv) $\cos(A+B)\cos(A-B)$
(a) $\cos^2 A - \sin^2 B$
(b) $\sin^2 A - \sin^2 B$
(c) $\tan \left(\frac{x+y}{2}\right)$
(d) $\cot \left(\frac{y-x}{2}\right)$
Answer:
Question 5. Match the product expression with the sum/difference equivalent:
(i) $\sin 3\theta \cos \theta$
(ii) $\cos 4\theta \cos 2\theta$
(iii) $\sin 5x \sin x$
(iv) $\cos 2x \sin x$
(a) $\frac{1}{2}(\cos 3x - \cos 5x)$
(b) $\frac{1}{2}(\sin 4\theta + \sin 2\theta)$
(c) $\frac{1}{2}(\cos 6\theta + \cos 2\theta)$
(d) $\frac{1}{2}(\sin 3x - \sin x)$
Answer:
Trigonometric Equations: Solving Methods
Question 1. Match the trigonometric equation with its principal solution in the interval $[0, 2\pi)$:
(i) $\sin x = 1$
(ii) $\cos x = 0$
(iii) $\tan x = \sqrt{3}$
(iv) $\cos x = -1$
(a) $\pi$
(b) $\frac{\pi}{2}, \frac{3\pi}{2}$
(c) $\frac{\pi}{3}, \frac{4\pi}{3}$
(d) $\frac{\pi}{2}$
Answer:
Question 2. Match the trigonometric equation with its general solution (where $n \in \mathbb{Z}$, $\alpha$ is principal value):
(i) $\sin x = \sin \alpha$
(ii) $\cos x = \cos \alpha$
(iii) $\tan x = \tan \alpha$
(iv) $\sin^2 x = \sin^2 \alpha$
(a) $x = n\pi \pm \alpha$
(b) $x = n\pi + \alpha$
(c) $x = 2n\pi \pm \alpha$
(d) $x = n\pi + (-1)^n \alpha$
Answer:
Question 3. Match the trigonometric equation with one of its solutions:
(i) $\sin x = 0$
(ii) $\cos x = 1$
(iii) $\tan x = 1$
(iv) $\sin x = -1$
(a) $2\pi$
(b) $\frac{\pi}{4}$
(c) $3\pi$
(d) $\frac{3\pi}{2}$
Answer:
Question 4. Match the equation type with a method of solving:
(i) Quadratic in $\sin x$ or $\cos x$
(ii) Involving different angles (e.g., $\sin 2x = \sin x$)
(iii) Simple equation $\sin x = k$
(iv) Involving sum/difference of terms (e.g., $\sin 3x + \sin x = 0$)
(a) Use sum-to-product formulas
(b) Use double/multiple angle identities
(c) Factorization or quadratic formula
(d) Find principal solution and use general solution formula
Answer:
Question 5. Match the given value with the trigonometric equation it might satisfy:
(i) $x = \pi/6$
(ii) $x = \pi/3$
(iii) $x = \pi/4$
(iv) $x = 0$
(a) $\tan x = 1$
(b) $\cos x = 1$
(c) $\sin x = 1/2$
(d) $\cos x = 1/2$
Answer:
Question 6. Match the general solutions (for $n \in \mathbb{Z}$):
(i) $\sin x = 1/2$
(ii) $\cos x = \sqrt{3}/2$
(iii) $\tan x = 1/\sqrt{3}$
(iv) $\sin x = -1/\sqrt{2}$
(a) $x = n\pi + (-1)^n (-\pi/4)$
(b) $x = n\pi + \pi/6$
(c) $x = 2n\pi \pm \pi/6$
(d) $x = n\pi + (-1)^n \pi/6$
Answer:
Inverse Trigonometric Functions: Introduction and Properties
Question 1. Match the inverse trigonometric function with its domain:
(i) $\sin^{-1} x$
(ii) $\cos^{-1} x$
(iii) $\tan^{-1} x$
(iv) $\sec^{-1} x$
(a) $\mathbb{R}$
(b) $[-1, 1]$
(c) $[-1, 1]$
(d) $\mathbb{R} - (-1, 1)$
Answer:
Question 2. Match the inverse trigonometric function with its principal value branch (range):
(i) $\sin^{-1} x$
(ii) $\cos^{-1} x$
(iii) $\tan^{-1} x$
(iv) $\text{cosec}^{-1} x$
(a) $(-\frac{\pi}{2}, \frac{\pi}{2})$
(b) $[-\frac{\pi}{2}, \frac{\pi}{2}]$
(c) $[0, \pi]$
(d) $[-\frac{\pi}{2}, \frac{\pi}{2}] - \{0\}$
Answer:
Question 3. Match the value of the expression:
(i) $\sin^{-1} (\frac{\sqrt{3}}{2})$
(ii) $\cos^{-1} (-\frac{1}{2})$
(iii) $\tan^{-1} (-1)$
(iv) $\sin^{-1} (\sin \frac{2\pi}{3})$
(a) $\frac{\pi}{3}$
(b) $\frac{2\pi}{3}$
(c) $-\frac{\pi}{4}$
(d) $\frac{\pi}{3}$
Answer:
Question 4. Match the inverse trigonometric identity with its simplified form:
(i) $\sin^{-1} x + \cos^{-1} x$
(ii) $\tan^{-1} x + \cot^{-1} x$
(iii) $\sec^{-1} x + \text{cosec}^{-1} x$
(iv) $\sin^{-1} (-x)$
(a) $\pi/2$
(b) $-\sin^{-1} x$
(c) $\pi/2$
(d) $\pi/2$
Answer:
Question 5. Match the function composition with the simplified expression (for appropriate domain and range):
(i) $\sin (\sin^{-1} x)$
(ii) $\cos (\cos^{-1} x)$
(iii) $\tan (\tan^{-1} x)$
(iv) $\sin (\cos^{-1} x)$
(a) $x$
(b) $\sqrt{1-x^2}$
(c) $x$
(d) $x$
Answer:
Question 6. Match the expression with its value:
(i) $\tan^{-1} (\tan \frac{\pi}{4})$
(ii) $\sin^{-1} (\cos 0)$
(iii) $\cos^{-1} (\sin \frac{\pi}{2})$
(iv) $\sin^{-1} (1) + \cos^{-1} (1)$
(a) $\pi/2$
(b) $\pi/4$
(c) $\pi/2$
(d) $\pi/2$
Answer:
Applications of Trigonometry: Heights and Distances
Question 1. Match the terms with their definitions:
(i) Angle of Elevation
(ii) Angle of Depression
(iii) Line of Sight
(iv) Horizontal Level
(a) The line from the observer's eye to the object.
(b) The angle between the horizontal line and the line of sight when looking downwards.
(c) The angle between the horizontal line and the line of sight when looking upwards.
(d) A line parallel to the ground passing through the observer's eye.
Answer:
Question 2. Match the scenario with the appropriate trigonometric ratio to find the height (h) or distance (x):
(i) Given angle of elevation $\theta$ and adjacent distance x, find h.
(ii) Given angle of elevation $\theta$ and hypotenuse (line of sight) L, find h.
(iii) Given angle of depression $\phi$ and horizontal distance x, find height difference h.
(iv) Given angle of elevation $\theta$ and opposite side h, find x.
(a) $\tan \phi = h/x$
(b) $\tan \theta = h/x$
(c) $\sin \theta = h/L$
(d) $\tan \theta = h/x$
Answer:
Question 3. In a problem involving angle of elevation $30^\circ$ and distance $30\ \text{m}$, match the calculation with the result:
(i) Height of object (using tangent)
(ii) Hypotenuse (using cosine)
(iii) Hypotenuse (using sine)
(iv) Adjacent side (using cotangent)
(a) $60\ \text{m}$ (if opposite = 30)
(b) $10\sqrt{3}\ \text{m}$
(c) $20\sqrt{3}\ \text{m}$ (if adjacent = 30)
(d) $30\sqrt{3}\ \text{m}$ (if opposite = 30)
Answer:
Question 4. Match the height of a tower with the given conditions:
(i) Distance from foot $30\ \text{m}$, angle of elevation $30^\circ$
(ii) Distance from foot $10\ \text{m}$, angle of elevation $60^\circ$
(iii) Shadow length $50\sqrt{3}\ \text{m}$, sun's altitude $30^\circ$
(iv) Angle of elevation changes from $30^\circ$ to $45^\circ$ as observer moves $100\ \text{m}$ towards tower
(a) $100(\sqrt{3}+1)\ \text{m}$
(b) $50\ \text{m}$
(c) $10\sqrt{3}\ \text{m}$
(d) $30\sqrt{3}\ \text{m}$
Answer:
Question 5. Match the scenario with the method to find the unknown height or distance:
(i) Tower and building problem (angles of elevation/depression from building top)
(ii) Two points on ground, same line as base (different angles of elevation)
(iii) Cloud and its reflection in water (angles of elevation/depression from a point above water)
(iv) Tree broken by wind
(a) Use trigonometric ratios in two right triangles and relate them using horizontal distance.
(b) Sum of the broken part (hypotenuse) and the standing part (adjacent/opposite).
(c) Use trigonometric ratios in two right triangles and relate them using the height difference and equal horizontal distance.
(d) Use trigonometry to find the height of the cloud and the depth of the reflection.
Answer: