NCERT Solutions Class 10 Maths Chapter 9 — Some Applications of Trigonometry#
Chapter 9 applies trigonometry to find heights and distances that cannot be measured directly. Using the concepts of angle of elevation and angle of depression, you will solve a variety of real-life problems involving towers, buildings, cliffs, and moving objects.
Exercises#
- Exercise 9.1 — Heights and distances using angles of elevation and depression (15 questions)
What you will learn#
- The line of sight, the angle of elevation and the angle of depression.
- Drawing a clear figure and spotting the right triangle in a word problem.
- Finding heights of towers and buildings and distances of ships and objects.
Key formulas and results#
- In most problems, $\tan\theta = \dfrac{\text{height}}{\text{horizontal distance}}$.
- $\tan 30° = \dfrac{1}{\sqrt{3}}$, $\tan 45° = 1$ and $\tan 60° = \sqrt{3}$.
Read and revise#
- Class 10 Maths Notes — Some Applications of Trigonometry: every definition, formula and method in short.
- All Class 10 Maths formulas on one page.
- NCERT Class 10 Maths Chapter 9 (PDF) — the textbook chapter itself, and all Class 10 Maths chapters.
Frequently asked questions#
How many exercises are in Class 10 Maths Chapter 9?
One: Exercise 9.1 (15 questions) — 15 questions in all, each solved step by step here.
Is the angle of depression equal to the angle of elevation?
Yes. The angle of depression from A to B equals the angle of elevation from B to A, because they are alternate angles between two horizontal lines.