Question

which formulas can be used to find the circumference of a circle? choose all that apply. $c = pi d$ $c = 2pi d$ $c = pi d^{2}$ $c = pi r$ $c = 2pi r$ $c = pi r^{2}$

Explanation:

Step1: Recall the formula for circumference in terms of diameter

The formula for the circumference \(C\) of a circle in terms of diameter \(d\) is \(C=\pi d\).

Step2: Recall the formula for circumference in terms of radius

Since \(d = 2r\) (where \(r\) is the radius), substituting \(d=2r\) into \(C=\pi d\) gives \(C=\pi(2r)=2\pi r\).

Answer:

\(C = \pi d\), \(C=2\pi r\)