Question

if \\(r\\) is the radius of a circle and \\(d\\) is its diameter, which of the following is an equivalent formula for the circumference \\(c = 2\pi r\\)?

a. \\(c = 2\pi d\\)
b. \\(c = \pi d\\)
c. \\(c = 2\pi d^2\\)
d. \\(c = 2\pi rd\\)

Explanation:

Identify the given variables

Using the Radius of a Circle and Diameter of a Circle knowledge points

$$
LATEXBLOCK0
$$

Substitute into the circumference formula

Using the Circumference Formula knowledge point

$$
LATEXBLOCK1
$$

Answer:

• (A) \(C = 2\pi d\)
• (B) \(C = \pi d\) (Correct answer)
• (C) \(C = 2\pi d^2\)
• (D) \(C = 2\pi rd\)