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Regular polygon area and apothem: Perimeter Calculator

Regular polygon area and apothem: Calculate perimeter from Area, Apothem. Check the formula, input units and worked result on this page.

Enter your values

cm²
Formula symbol: A. Required unit: cm². Must be greater than zero.
cm
Formula symbol: a. Required unit: cm. Must be greater than zero.

Use a decimal point, without thousands separators.

Lengths use cm, areas cm² and volumes cm³ on one consistent scale. The positive real branch is selected; the supplied quantities must describe the stated shape.
Example result
Perimeter
24 cm

The initial result uses the example values. Enter your own values and calculate again.

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How it works

The apothem is perpendicular from the centre to a side. Summing the central triangles gives half the product of apothem and perimeter. This form solves for perimeter; enter the known quantities in Area, Apothem.

Inputs and units
Regular polygon area and apothem: Perimeter Calculator · Inputs and units
InputExample valueWhat to enter
Area36 cm²Formula symbol: A. Required unit: cm². Must be greater than zero.
Apothem3 cmFormula symbol: a. Required unit: cm. Must be greater than zero.
P = 2A / a

Worked example

Show example inputs and results

This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.

Area
36 cm²
Apothem
3 cm

Complete example results

Perimeter
24 cm

Reading the result

The result solves for perimeter from the entered quantities. Check the result unit and the formula conditions before using it.

Questions and answers

Can I use the example values for my own calculation?

The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.

When can I use the perimeter result?

Lengths use cm, areas cm² and volumes cm³ on one consistent scale. The positive real branch is selected; the supplied quantities must describe the stated shape.

Why are some results rounded?

Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.

Are my inputs sent to a server?

The calculator processes inputs in your browser. Its code does not send your values to a server.

Method sources: openstax.org

Methods & accuracy

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