Answer:
x = 12.5
Step-by-step explanation:
The large outer triangle and the small inner triangle are similar, thus the ratio of their corresponding sides are equal, that is
[tex]\frac{20}{6x-7}[/tex] = [tex]\frac{15}{15+36}[/tex] = [tex]\frac{15}{51}[/tex] ( cross- multiply )
15(6x - 7) = 1020 ( divide both sides by 15 )
6x - 7 = 68 ( add 7 to both sides )
6x = 75 ( divide both sides by 6 )
x = 12.5
