# What is the circumference of a circle with a diameter of 16 in?

Sep 22, 2015

$16 \pi$

#### Explanation:

We have that the circumference C is $\pi \cdot 2 r$ or $\pi \cdot d$, that's because $\pi$ was defined as the ratio between the circumference and the diameter. So, axiomatically:

$\frac{C}{d} = \pi$, therefore $C = \pi \cdot d$

Sep 22, 2015

$C = 50. \text{in}$
The formula for calculating the circumference of a circle is $C = \pi \cdot d$, where $\pi$ is $3.1415 \ldots$ and $d$ is the diameter.
$C = \pi \cdot 16 \text{in"=50.265482457437 "in"=50. "in}$ (with two significant figures)