If the radius of a coinis 20cm, find its
surface area -

800cm²

Explanation:

Given parameters:

radius of the coin  = 20cm

Unknown:

Surface area of the coin  = ?

Solution:

A coin is made up of two faces;

  Surface area  = 2(πr²)

Insert the parameters and solve;

     Surface area = 2()

    Surface area = 800cm²

force tends to be low and long diustance masses are high