Question

We need to cut a circular piece of cardboard with area 200 square centimeters. What will the radius of the circle be? (Round to the nearest whole number.)

Answer 1

The area of a circle can be calculated with the following formula:

$A=\pi r^2$

Where "r" is the radius of the circle.

In this case, you know that the area of the circular piece of cardboard is:

$A=200\operatorname{cm}^2$

Then, knowing the area, you can substitute it into the formula:

$200\operatorname{cm}^2=\pi r^2$

Finally, you have to solve for "r" in order to find the radius. Rounded to the nearest Whole number, the radius is:

$r\approx8\operatorname{cm}$