List of formulas in elementary geometry

This is a short list of some common mathematical shapes and figures and the formulas that describe them.

Two-dimensional shapes

Shape	Area	Perimeter/Circumference
Square (where ${\displaystyle s}$ is the length of a side)	${\displaystyle A=s^{2}}$	${\displaystyle P=4s}$
Rectangle ( ${\displaystyle l}$ is length, ${\displaystyle w}$ is width)	${\displaystyle A=lw}$	${\displaystyle P=2l+2w}$
Circle (where ${\displaystyle r}$ is the radius and ${\displaystyle d}$ is the diameter)	${\displaystyle A=\pi r^{2}}$	${\displaystyle C=2\pi r}$ or ${\displaystyle C=\pi d}$
Ellipse (where ${\displaystyle a}$ is the semimajor axis and ${\displaystyle b}$ is the semiminor axis)	${\displaystyle A=\pi ab}$
Triangle (${\displaystyle b}$ is base; ${\displaystyle h}$ is height; ${\displaystyle a,b,c}$ are sides)	${\displaystyle A={\frac {bh}{2}}}$	${\displaystyle P=a+b+c}$
Parallelogram (${\displaystyle b}$ is base, ${\displaystyle h}$ is height, ${\displaystyle a}$ is side)	${\displaystyle A=bh}$	${\displaystyle P=2a+2b}$
Trapezoid (where ${\displaystyle a}$ and ${\displaystyle b}$ are the bases)	${\displaystyle A={\frac {a+b}{2}}h}$

Sources:[1][2]

[3]

Three-dimensional shapes

Shape	Volume	Surface area
Cube (where ${\displaystyle s}$ is the length of a side)	${\displaystyle V=s^{3}}$	${\displaystyle 6s^{2}}$
Rectangular Prism (${\displaystyle l}$ = length, ${\displaystyle h}$ = height, ${\displaystyle w}$ = width)	${\displaystyle V=lwh}$	${\displaystyle S=2lw+2lh+2wh}$
Sphere (where ${\displaystyle r}$ is the radius)	${\displaystyle V={\frac {4\pi r^{3}}{3}}}$	${\displaystyle S=4\pi r^{2}}$
Right circular cylinder (where ${\displaystyle r}$ is the radius and ${\displaystyle h}$ is the height)	${\displaystyle V=\pi r^{2}h}$	${\displaystyle S=2\pi rh+2\pi r^{2}}$

Sources:[4]

References

1. "Archived copy" (PDF). Archived from the original (PDF) on 2012-08-13. Retrieved 2011-11-29.CS1 maint: archived copy as title (link)
2. http://www.math.com/tables/geometry/areas.htm
3. https://www.andlearning.org/geometry-formulas/
4. http://www.math.com/tables/geometry/volumes.htm