How do you find the area of a circle that has no diameter?

Answer 1

The circle must have a diameter, so maybe your teacher just didn't tell you the diameter. In order to figure out the question, you need to know some information about the circle. Weather it's the radius, circumference, or diameter. So here's how you find area if you only have each of the three:

1. If you just have the radius, then square the radius. This means multiply radius times radius. Or say the radius is 4. Squaring it is 4 times 4. So once you find out the answer for radius squared, multiply radius squared by pi. (Probably use 3.14 for pi) Then there's your area.

2. If you only have the circumference of a circle, then you need to find the radius. In order to do that, you need to find the diameter. To find the diameter of a circle, you take the circumference and divide it by pi. (3.14) then you have your diameter. Since the radius is half the diameter, divide the diameter by 2. Then, once you find the radius, you may look at step 1 and use those steps to find out the area.

Since your question is wondering how to find the area without knowing the diameter, then you can multiply the radius by 2 to find out the diameter. Even though you don't need to know the diameter to find the area. You just do (r times r) times pi (3.14)