Question

The inner and outer radii of a cyclindrical pipe are 4 cm and 5 cm respectively find the area of cross section of the pipe.

Answer 1

it's inner radius , r= 4
outer radius , R = 5
area of cross section = π ( R^2 - r^2)
= 3.14 ( 25- 16)
= 3.14 × 9
= 28.26 is the answer