Question

Find the circumference and area of a circle with a diameter of 10 inches. Leave your answers in terms of pi.

A)C = 5π; A = 20π


B)C = 10π; A = 20π


C)C = 10π; A = 25π


D)C = 5π; A = 25π

Answer 1

C) C = 10π ; A=25π

Explanation:

We are ask to find the circumference and area of a circle with a diameter of 10 inches, but we are to leave our answer in terms of π

First lets start by calculating the circumference.

The formula for calculating circumference of a circle is;

circumference = 2πr where r=radius

But we were given diameter in the question to be 10, r =
`(d)/(2)` =
`(10)/(2)` = 5

We can now proceed to insert our value into the equation

Circumference = 2 × π × 5 = 10π

Lets now go ahead to calculate the area of the circle

To calculate area of the circle, we use the formula;

Area = πr²

= π×5×5

=25π

Therefore C = 10π and A=25π

Answer 2

A = π • r^2
C = 2 • π • r

A = 25 π
C = 10 π

Your answer is C) 10π; A = 25π