Question

the circumference of a circle is 31.4cm find the radius and the area of the circle

Answer 1

Circumference of circle = 31.4 cm
2πr = 31.4 cm
r = 31.4/2π
r = 15.7/π
r = 15.7/3.14 = 5cm
Area of given circle = πr² = 3.14×5² = 78.5 cm²

Answer 2

Circumference = 31.4cm
2πr = 31.4
2 X 3.14 X r = 31.4
6.28r = 31.4
r = 31.4 / 6.28
= 31.4 X 100 / 6.28 X 100
= 3140 / 628
= 5
Radius = 5cm
Area = πr^2
= 3.14 X (5)^2
= 3.14 X 25
= 78.5m^2