Radius of a Circle

Written by Jerry Ratzlaff on . Posted in Plane Geometry

circle diameter 4Radius of a Circle formula

\(\large{ r = \frac {D} {2} }\)

\(\large{ r = \frac {C} {2 \pi} }\)

\(\large{ r = \sqrt   {\frac {A} {\pi} }  }\)

Where:

\(\large{ r }\) = radius

\(\large{ d }\) = diameter

\(\large{ C }\) = circumference

\(\large{ A }\) = area