Answer:
50
Step-by-step explanation:
The sum of the angles of a triangle is 180
A +B +C = 180
90 +4x+ 7x-20 =180
Combine like terms
70+ 11x = 180
Subtract 70 from each side
70-70+11x = 180-70
11x=110
Divide each side by 11
11x/11= 110/11
x = 10
We want to find angle C
C = 7x-20
= 7*10-20
= 70-20
= 50
50°
7x - 20 + 4x + 90 = 180
11x = 180 - 70
11x = 110
ACB: 7(10) - 20 = 50
