PERIMETER

The 'perimeter' is the distance around a given two-dimensional object. The word perimeter is a Greek root meaning measure around, or literally "around measure".

Contents

Practical uses

Formulas

Polygons

Circles

In General

See also

External links

Practical uses

Perimeter and area play a great role in today's world. Perimeter is used in calculating the border of an object such as a yard or flowerbed when a fence or other border is being installed around the edges. Area is used when all the area inside of a perimeter is being covered with something, such as a yard being covered with sod or fertilizer.

Formulas

Polygons

As a general rule, the perimeter of a polygon can always be calculated by adding all the length of the sides together.
So, the formula for triangles is $P=a+b+c$, where $a$, $b$ and $c$ stand for each side of it. For quadrilaterals the equation is $P=a+b+c+d$. For equilateral polygons, $P=na$, where ''n'' is the number of sides and ''a''
is the side length.

Circles

For circles the equation is
: $$
P = 2 cdot pi cdot r

or
: $$
P = d cdot pi


★ $P$ stands for the perimeter,

★ $r$ stands for the radius

★ $pi$ is the mathematical constant pi ($pi=3.14159265...$)

★ $d$ stands for the circle's diameter (twice the radius of a circle)
(The dot means multiply or times)

In General

If r is considered to be the distance from the centre of a regular polygon to one of its vertices (or in the case of a circle, the radius), the following holds true:
:

★ $P$ stands for the perimeter,

★ $r$ stands for the radius

★ $A$ stands for the area

See also

★ Isoperimetric Theorem

★ Circumference

★ Pythagorean Theorem

★ Wetted perimeter

External links