Question

Radius of two circle is 20 cm and 13 cm . Fund the difference between their circumferences.

Answer 1

circumference of the circle of radius 20cm =$2\pi20$
=$40\pi$ circumference of circle of 13cm =$2 \pi13$
=$26\pi$
so, difference of circumference = $40\pi - 26\pi$
=$14\pi$
=$14 \times 22 \div 7$
=$2 \times 22$
=44
so the ans is 44cm

Answer 2

circumference of circle of Radius 1 = 2πr
circumference of circle of radius 2 = 2πr
2πR - 2πr
2×22/7×20 - 2×22/7×13
2×440/7 -2×286/7
880/7-572/7
308/7
= 44