Question

se os ângulos com "marcas iguais" são congruentes, determine x.

Answer 1

Simplificamos:
A)
x/10 = 18:³/15:³
x/10 = 6/5
x = (10*6)/5
x = 60/5
x = 12

B)
15:^5/5 = 21/x
3 = 21/x
3x = 21
x = 21/3
x = 7