The area of a circle with radius r is calculated using the formula below.
A=Ï€ r^2
We know that the area of the circle is 12.6 in^2. By substituting 12.6 for A in the formula, we can calculate r.
The radius of the circle is a measurement and therefore cannot be negative. This means we will only use the positive result. We know that the diameter of a circle is exactly twice as long as its radius. With that information we can calculate the diameter.
D = 2r
D = 2( 2.002674 ...)
D = 4.005348 ...
The diameter of the circle is approximately 4.01 inches.
