Question

question 1 of 10 what is cos 30°? 60° 2 1 90° 30° √3 a. $\frac{1}{sqrt{3}}$ b. $\frac{sqrt{3}}{2}$ c. $sqrt{3}$ d. $\frac{1}{2}$ e. $\frac{1}{sqrt{2}}$ f. 1

Explanation:

Step1: Recall cosine formula

In a right - triangle, $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$.

Step2: Identify sides for 30 - degree angle

For a 30 - 60 - 90 triangle with hypotenuse $c = 2$, and the side adjacent to the 30 - degree angle $a=\sqrt{3}$.

Step3: Calculate cos 30°

$\cos30^{\circ}=\frac{\sqrt{3}}{2}$

Answer:

B. $\frac{\sqrt{3}}{2}$