Q. 1 - Precalculus Enhanced with Graphing Utilities

Question

What is the formula for the circumference $C$ of a circle of radius $r$ ? What is the formula for the area $A$ of a circle of radius $r$ ?

Step-by-Step Solution

Answer

The solution is $C=2\mathrm{\pi r} , \mathrm{A}={\mathrm{\pi r}}^2$ .

Step 1. Given information

Circumference $C$ of a circle of radius $r$ and area $A$ of a circle of radius $r$ .

Step 2. Calculation

The formula for the circumference $C$ of a circle of radius $r$ is -

$C=2\mathrm{\pi r}=\mathrm{\pi d}$ , where $d$ is the diameter

The formula for the area $A$ of a circle of radius $r$ is -

$A={\mathrm{\pi r}}^2$