Question

Find y.

A. 42–√
B. 4
C. 22–√
D. 83√3

Answer 1

4, or B

Explanation:

Answer 2

B

Explanation:

You always have to use the Big Three trig functions (those that are on your calculator when answering this kind of question involving right angle triangles).

y is the adjacent side of the triangle. It is the side (other than the hypotenuse -- which is the longest side of the right triangle) that makes up the cosine.

Cos(45) = y / 4 sqrt(2)

Cos(45) = sqrt(2)/2

Multiply both sides by 4 sqrt(2)

4*sqrt(2) * cos(45) = y

4*sqrt(2) * sqrt(2)/2 = y

2*2 = y

y = 4

I can't tell you where all the other choices are coming from.