Question

ABC is a right angled triangle.
If $\alpha ={30}^{\circ }$ and AC = 10 cm then find the length of side BC in cm.

• A. 5

Answer 1

The correct option is A 5
We know that,

$sin\alpha =\frac{\text{opposite side}}{\text{hypotenuse}}=\frac{BC}{AC}$

$sin\alpha =sin{30}^{\circ }=\frac{1}{2}$

$\text{Thus,}\frac{BC}{AC}=\frac{BC}{10}=\frac{1}{2}$

$BC=\frac{10}{2}=5cm$