Perimeter of Regular Polygon
Theorem
Let $P$ be a regular $n$-sided polygon whose side length is $b$.
Then the perimeter $L$ of $P$ is given by:
- $L = n b$
Proof
By definition, an $n$-sided polygon has $n$ sides.
By definition, a regular polygon has sides all the same length.
By definition, the perimeter of a polygon is the total length of all its sides.
Thus $P$ has $n$ sides all of length $b$.
Hence $L = n b$.
$\blacksquare$
Sources
- 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 4$: Geometric Formulas: Regular Polygon of $n$ Sides Each of Length $b$: $4.10$
- 2009: Murray R. Spiegel, Seymour Lipschutz and John Liu: Mathematical Handbook of Formulas and Tables (3rd ed.) ... (previous) ... (next): $\S 7$: Geometric Formulas: Regular Polygon of $n$ Sides Each of Length $b$: $7.10.$