Question

Suppose the diameter of a circle is 10. What is its area?

Answer 1

To find area you must use the formula A= pi*radius. So the radius is always 1/2 of the diameter. 10/2 is 5.So your radius is 5. multiply 5 by 3.14, to get the area of 78.54

Answer 2

Well hello again :3. This is also quite simple. The diameter of a circle is 2 times the radius. So we can refit this into the equation and say that our new formula using diameter is
`pi(d^2/2)`. Now we can say that 10/2 is 5 and
`5^2` is 25. Therefore your answer is
`25pi` or 78.54.