Question

select the correct answer.
what is the value of x?
triangle with right angle at top, one base angle 45°, base length 15, side labeled x
a. 7.5
b. 21.2
c. 15
d. 10.6

Explanation:

Step1: Identify triangle type

It's a 45-45-90 right triangle.

Step2: Use cosine function

$\cos(45^\circ) = \frac{x}{15}$

Step3: Solve for x

$x = 15 \times \cos(45^\circ) = 15 \times \frac{\sqrt{2}}{2} \approx 15 \times 0.7071 \approx 10.6$

Answer:

D. 10.6