Question

The area of a circle is 78.5 sq.cm. Calculate the circumference of the circle [Taken π=3.14].

Answer 1

Given: Area of circle = 78.5cm²

πr² = 78.5

⇒ 3.14 r² = 78.5

⇒ r² = 78.5/3.14

⇒ r² = 25

⇒ r = ± 5

⇒ r = 5cm

[taking positive root, because radius can’t be negative]

Now, circumference of circle = 2πr

= 2 × 3.14 × 5

= 31.4cm