Formulary : Maths - Geometry

Circle ○

A circle is a basic shape consisting of the points at a given distance from a given point on a plane.

The circumference U is the distance around a closed curve.

${\color{blue} {U}} = 2 \times \pi \times {\color{red} {r} }$

U = Circumference

r = Radius

${\color{red} {r}} = \frac{ {\color{blue} {U} } }{ 2 \times \pi }$

r = Radius

U = Circumference

${\color{blue} {U}} = \pi \times {\color{red} {d} }$

U = Circumference

d = Diameter

${\color{red} {d}} = \frac{ {\color{blue} {U} } }{ \pi }$

d = Diameter

U = Circumference

The region inside a circle.

${\color{OliveGreen} {A}} = \pi \times {\color{red} {r} }^{2}$

A = Area

r = Radius

${\color{red} {r}} = \sqrt{ \frac{\color{OliveGreen} {A}}{\pi} }$

r = Radius

A = Area

${\color{OliveGreen} {A}} = \frac{\pi}{4} \times {\color{red} {d} }^{2}$

A = Area

d = Diameter

${\color{red} {d}} = \sqrt{ \frac{4 \times {\color{OliveGreen} {A} } }{\pi}}$

d = Diameter

A = Area