calqulio.
◎ English · Global

Regular polygon apothem conversion: Circumradius Calculator

Regular polygon apothem conversion: Calculate circumradius from Apothem, Side count. Check the formula, input units and worked result on this page.

Enter your values

cm
Formula symbol: a. Required unit: cm. Must be greater than zero.
Formula symbol: n. Enter a numeric value. Use a whole number. Must be greater than zero. Allowed range: 3–10,000.

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
Circumradius
4 cm

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

Edit inputs

How it works

The apothem reaches a side midpoint; the circumradius reaches a vertex. The half central triangle has angle π/n radians. This form solves for circumradius; enter the known quantities in Apothem, Side count.

Inputs and units
Regular polygon apothem conversion: Circumradius Calculator · Inputs and units
InputExample valueWhat to enter
Apothem3.4641016151377544 cmFormula symbol: a. Required unit: cm. Must be greater than zero.
Side count6Formula symbol: n. Enter a numeric value. Use a whole number. Must be greater than zero. Allowed range: 3–10,000.
R = a / cos(π/n)

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.

Apothem
3.4641016151377544 cm
Side count
6

Complete example results

Circumradius
4 cm

Reading the result

The result solves for circumradius 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 circumradius 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

What would you like to calculate?

Browse all calculators

Graphing calculator ↗