Question

what is the formula that relates circumference and radius?
a. c = 2π/r
b. c = 2πr
c. c = 2πd
d. c + 2 = πr

Explanation:

Step1: Recall circle - related knowledge

The circumference $C$ of a circle is related to its radius $r$.

Step2: Identify the correct formula

The standard formula for the circumference of a circle in terms of radius is $C = 2\pi r$, where $\pi$ is a mathematical constant approximately equal to 3.14159.

Answer:

B. $C = 2\pi r$