Question

the circumference of a circle exceeds its dieameter by 30cm. Find the circumference of a circle.​

Answer 1

Let the radius of the circle be = r cm

Circumference of the circle = 2πr

Given that Circumference = Diameter + 30 cm

Diameter = 2r

2πr = 2r + 30

2πr – 2r = 30

By taking 2r common we get

2r (π – 1) = 30

2r × (22/7 – 1) = 30

2r × (22 – 7) = 30

7

2r × (15/7) = 30

2r × 15 = 30 × 7

r = 30 × 7

2 × 15

r = 7 cm

Circumference of the circle = 2πr

= 2 × 22 × 7

7

= 2 × 22

= 44 cms