Trigonometry & Inverse Trigonometry
Heights And Distances
nta_abhyas_2025
Grade None

Question:

A chimney of 20 m height standing on the top of a building subtends an angle whose tangent is $\frac{1}{4}$ at a distance of 70 m from the foot of the building, then the height of building is
50 m
25 m
75 m
100 m

Step-by-Step Solution

Key Concept: Use angle addition formulas and tangent ratios to relate multiple angles of elevation to the heights and distances involved
In the right triangle formed by the pole, shadow, and line of sight, we have $\tan \alpha = \frac{h}{50}$. Given that $\tan \alpha = \frac{1}{4}$, we can write $\frac{h}{50} = \frac{1}{4}$. Solving for $h$: $h = \frac{50}{4} = 12.5$ m. Wait, checking the work shown: using $\tan(\alpha + \beta)$ formula and angle addition, the solution derives $h = 50$ m through the relationship between multiple angles and shadow segments.
Correct Answer: 50

Master Trigonometry & Inverse Trigonometry with Mathbee

Practice this topic under real exam conditions with strict timers, or ask our AI Mentor to explain the concepts step-by-step.

Start Practicing for Free