Triangle abc is a right triangle and cos(22.6o)=b/13. solve for b and round to the nearest whole number.
which equation correctly uses the value of b to solve for a?

tan(22.6o) = a/13
tan(22.6o) =13/a
tan(22.6o) = a/12
tan(22.6o) = 12/a

The cosine of an angle is equal to the adjacent side divided by the hypotenuse. In a right triangle, the hypotenuse is the longest side. Its value is 13. It also follows that B is the adjacent side.

To solve for B,

B = 13 cos 22.6˚ = 12

The tangent of the angle is equal to the opposite side divided by the adjacent side. Since B is known, therefore the answer is

tan(22.6˚) = a/12