What is a regular polygon?

A regular polygon has all sides and angles equal (e.g. equilateral triangle, square, pentagon).

What formulas are used?

With n sides and side length s: perimeter = n×s; area = (n×s²)/(4×tan(π/n)). With circumradius R: side = 2R×sin(π/n).

Calculate area and perimeter of a regular polygon from number of sides and side length (or circumradius).

Number of sides

Given

Side lengthCircumradius

Side length

What is a regular polygon?: A regular polygon has all sides and angles equal (e.g. equilateral triangle, square, pentagon).
What formulas are used?: With n sides and side length s: perimeter = n×s; area = (n×s²)/(4×tan(π/n)). With circumradius R: side = 2R×sin(π/n).

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