If the diameter of an circle is 20mm what is the area?

Answer 1

For a circle with a diameter of 20 mm, it's radius, which is half that, will be 10 mm. The area (A) of a circle is pi (about 3.1416) times the radius (r) squared (r2). Here's how we work it: Acircle = pi x r2 = 3.1416 x 102 = 3.1416 x 100 = 314.16 mm2