Question

question 24 of 25
knowing that sin 30° = $\frac{1}{2}$, what is a?
a. 8.66
b. 5
c. 10
d. 2.5

Explanation:

Step1: Recall sine - definition

In a right - triangle, $\sin\theta=\frac{\text{opposite}}{\text{hypotenuse}}$. Here, $\theta = 30^{\circ}$, the side opposite the $30^{\circ}$ angle is $5$ and the hypotenuse is $a$.

Step2: Apply the sine formula

We know that $\sin30^{\circ}=\frac{5}{a}$. Since $\sin30^{\circ}=\frac{1}{2}$, we have the equation $\frac{1}{2}=\frac{5}{a}$.

Step3: Solve for $a$

Cross - multiply to get $a\times1 = 5\times2$. So, $a = 10$.

Answer:

C. 10