Plz helppp!

Identify each situation that would require the application of surface area.

What is the first step of an indirect proof of a number that is divisible by two

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

You have 12 balloons to blow up for your birthday party. you blow up 1/3, and your friend blows up 5 of them. what fraction of the baloons still need blowing up