The top of a round table with a diameter of 5.5 feet is painted white. how many square feet are painted

Iam so stuck. what is the worked out answer for this question?

If u good at math hit me up on insta or sum @basic_jaiden or @ and

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?