Help ill give brainliest pls help help

Select the lengths in centimeters that would form a right triangle

Ineed some on this. not sure how to solve.

Agroup of five people go out to eat and buy appetizers and main dishes they decide to split the bill so each person pays 20% of the total cost appetizers are $5 and main dishes are $10 write an expression to show how much each person pays explain it with how to solve the problem