I learned this recently and its a piece of pie! XD
Pi=3.14 or 22/7.
Radius- a straight line from the center to the circumference of a circle or sphere.
I'll hand you over a formula for this and you can plug the numbers in!
Radius= Diameter/2
Area= Pi x (Radius to the 2nd power)
Diameter= 2 x Radius
I hope this helps in some way!
