Answer:
Explanation:
Cos(R) = adjacent / hypotenuse
Adjacent is the side connected to the angle
Adjacent = 12
Hypotenuse = 13
Cos(R) = 12 / 13 = .9231
Now you find R by taking the inverse cos of (R). On most calculators it is 2nd function cos
R = cos-1(0.9231)
Answer: R = 22.62 degrees