Question

In the given right angle triangle ABC, if $\alpha ={30}^{\circ }$ and AC = 10 cm then find the value of the side BC in cm.

• A. 5
• B. 2
• C. 3
• D. 1

Answer 1

The correct option is A

5

Trigonometric ratio ,
$sin\alpha =\frac{oppositeside}{hypotenuseside}=\frac{BC}{AC}$

Given, $\alpha ={30}^{\circ }$ and AC = 10 cm.
We have, $sin{30}^{\circ }=\frac{1}{2}$.
$\therefore \frac{BC}{AC}=\frac{1}{2}$

$\Rightarrow \frac{BC}{10}=\frac{1}{2}$

$\Rightarrow BC=5cm$