Question

a circular mirror has a radius of 4 inches.
what is the circumference of this mirror?
2π inches
4π inches
8π inches
16π inches

Explanation:

Step1: Recall the formula for circumference

The formula for the circumference of a circle is \(C = 2\pi r\) or \(C=\pi d\) (where \(r\) is the radius and \(d\) is the diameter, and \(d = 2r\)). Given \(r = 4\) inches, then \(d=2\times4 = 8\) inches.

Step2: Substitute into the formula

Using \(C=\pi d\), substitute \(d = 8\) into the formula. So \(C=\pi\times8=8\pi\) inches.

Answer:

C. \(8\pi\) inches