What is 90% in the simplest form?

The answer is 7.2 how would you put this as money

Select each option that represent a proportional relationship between x and y.

Determine the value of x for which r ∥ s if m∠1 = 73 – 2x; and m∠2 = 89 – 3x. i would like if someone could show me how to solve this, !