Answer:
4. x = 23 degrees
5. m<A = 33 degrees
m<B = 66 degrees
m<C = 82 degrees
Explanation:
4.
(2x + 21) + 90 degrees + x = 180 degrees
(2x + 21) + x = 90 degrees
3x + 21 = 90
3x = 69
x = 23 degrees
5.
2x + x + (2x + 15) = 180 degrees
5x + 15 = 180
5x = 165
x = 33