How hard body decompose

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

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Is the power produced directly proportional to the wind speed, give reasons for your answer?