Write an algebraic expression for the product of a number and 17

Is δ pmr similar to δ smn ? if so, which postulate or theorem proves these two triangles are similar?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.