How to find the area of an annulus
The area = π x (Outer Radius 2 – Inner radius 2)
Example:
π = 3.14
Outer Radius = 10 cm
Inner radius = 8 cm
Area = 3.14 x (102 – 82)
Outer Radius = 10 cm
Inner radius = 8 cm
Area = 3.14 x (102 – 82)
ANSWER : 113 cm2
Tools you'll need
what a good stuff, more enough than refresher course