Please somebody help me with this problem:

**A boy wants to knock down a coconut with a rock and his slingshot. He observes that the coconut is about 3.0m above his slingshot and the tree is 4.0m away along the ground.**

He knows from experience that the release speed of his rock is 20m/s.

How far above the coconut should he aim?

He knows from experience that the release speed of his rock is 20m/s.

How far above the coconut should he aim?

Please can someone help me?

thank you

B.