how do i get the answer for this?

Answer:
x = 5
Step-by-step explanation:
The total amount is 90°, so form an equation.
10x + 8x = 90(°)
Then combine like terms.
18x = 90(°)
Divide 90 by 18 to get X by itself.
90/18 = 5
x = 5
HOPE THIS HELPS PLEASE MARK BRAINLIEST!