Question

the circumference of a compact disc is 21.98cm.find it's radius​

Answer 1

Answer:

the radius of circle is 4 cm

Answer 2

$\huge \dag \: { \boxed{ \underline{ \sf{ \pink{Answer}}}}}$

Compact disk is in the shape of a circle. Hence the circumference of a compact disk can be equated to that of a circle.

Circumference of Circle = 28.26 cm

We know that Circumference of a circle is 2πr, where r is the radius of the circle.

Hence substituting them in the formula we get,

2πr = 28.26

2 ×3.14 ×r = 28.26

6.28 ×r = 28.26

r = 28.26 / 6.28

r = 4.5 cm

Hence the radius of the compact disk ( CD ) is 4.5 cm.