Using a radius of:
The
is
square units.
The is
units.
Using a diameter of: The
is
square units.
The is
units.
11. Circle's arcs and sectors
Though
radians make these formulas MUCH easier and clearer, this part of the page uses only degrees to measure angles and builds the conversion from degree to radian into the formulas. In the list of units shown below and the other images, the conversion formula is visible.
The
radians page also has a calculator to convert from radians (based on a circle's angle measure of 2
) to degrees (based on a circle's angle measure of 360°).