Find cos(a) Reduce the ratio if necessary

3/5 Choice 4.

Step-by-step explanation:

Remember SOH, CAH, TOA.

Sine=opposite/hypotenuse

Cosine=Adjacent/hypotenuse

Tangent=Opposite/adjacent.

Since we are looking for Cosine, we would need to locate the adjacent and hypotenuse of angle a.

The hypotenuse is the easiest to find because that will simply be the longest side of the triangle(50)

The adjacent would be 30 because 40 is the opposite(right across from theta).

So, A=30

H=50

Simply that to get Cos(A)=.