Answer:
Y = theta = 32.68
Explanation:
Formula
y^2 = x^2 + z^2 - 2*x*z * cos(theta)
Givens
y = 55
theta = ?
z = 50
x = 90
Solution
55^2 = 90^2 + 50^2 - 2*90*50 cos(theta)
3025 = 8100 + 2500 - 9000 cos(theta) Combine the right
3025 = 10600 - 9000 Cos(theta) Subtract 10600
3025 - 10600 = -9000 Cos(theta)
-7575 = - 9000 Cos(theta) Divide by - 9000
-7575/-9000 = cos(theta)
0.8417 = cos(theta)
cos-1(0.8417) = theta
theta = 32.68