Question

One circle has a diameter of 10 inches. A second circle has a diameter that is twice the diameter of the first circle. What is the ratio of the area of the smaller circle to the larger circle?

Answer 1

`78.54:314.16`

Explanation:

First circle area with diameter 10 inches =

`\pi r^2`

`\pi * 5^2`

`=78.53981`

Second circle area with diameter 20 inches =

`\pi r^2`

`\pi * 10^2`

`=314.159265`

`78.53981:314.159265`

Answer 2

78.5 : 314.2

Explanation:

Diameter of the first Circle = 10 inches

Diameter of the second Circle = 2(10) [TWICE] = 20 inches

So,

Area of the first circle:

Radius = 5 inches

Area = πr²

A = (3.14)(5)²

A = 78.5 inches²

Area of the second circle:

Radius = 10 inches

Area = πr²

Area = (3.14)(10)²

Area = 314. 2 inches

Now the ratio of the area of smaller circle to the larger circle is

78.5 : 314.2