Question

The radius of a circle is 14cm. Find the radius of the circle whose area is double of the area of circle. ​

Answer 1

19.8cm

Explanation:

First find area of small circle:

A = πr2

A = 22/7 x 14 x 14

A = 22 x 2 x 14

A = 616cm2

Area of bigger circle is double that of the small circle:

= 616 x 2

= 1,232 cm2

πR2 = A

22/7 x r2 = 1,232

r2 = (1,232 x 7) ÷ 22

r2 = 8624 ÷ 22

`\sqrt{r ^(2) } = √(392)`

radius of bigger circle = 19.8cm

Answer 2

• 14√2 cm

Explanation:

Area of circle equation:

• A = πr²

Let the radius of bigger circle is x.

We have:

• π(14²)*2 = πx²

Solve for x:

• x² = 2(14²)
• x = √2(14²)
• x = 14√2 cm