Question

Taking n = 3.14, find the radius and circumference of a circle whose area is :
(i) 200.96 cm
(ii) 379.94 m2
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Answer 1

Case 1 :-

Given :

• Area of circle = 200.96 cm²

★ Area of circle = πr²

→ 200.96 = 3.14 × r²

→ r² = 200.96/3.14

→ r² = 64

→ r = √64

→ r = 8 cm

∴ Radius of circle = 8 cm

★ Circumference of circle = 2πr

→ 2 × 3.14 × 8

→ 50.24 cm

∴ Circumference of circle = 50.24 cm

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Case 2 :-

Given :

• Area of circle = 379.94 m²

★ Area of circle = πr²

→ 379.94 = 3.14 × r²

→ r² = 379.94/3.14

→ r² = 121

→ r = √121

→ r = 11 m

∴ Radius of circle = 11 m

★ Circumference of circle = 2πr

→ 2 × 3.14 × 11

→ 50.24 cm

∴ Circumference of circle = 69.08 m