Question

question 10 of 10
what is cos 30°?
a. √3
b. √3/2
c. 1/√2
d. 1
e. 1/√3
f. 1/2

Explanation:

Step1: Recall the cosine formula

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

Step2: Identify the sides for \(\theta = 30^{\circ}\)

For the \(30^{\circ}-60^{\circ}-90^{\circ}\) triangle, the adjacent side to the \(30^{\circ}\) angle is \(\sqrt{3}\) and the hypotenuse is \(2\).

Step3: Calculate \(\cos30^{\circ}\)

\(\cos30^{\circ}=\frac{\sqrt{3}}{2}\)

Answer:

B. \(\frac{\sqrt{3}}{2}\)