pi (π)=3.1415926535 ...
| Shape | Formula | |
|---|---|---|
| ◯ | Circle | P= 2 × pi × radius |
| ◻ | Square | P= 4 × side |
| ⌷ | Rectangle | P= 2 × (length + width) |
| ▱ | Parallelogram | P = 2 × (side1 + side2) |
| △ | Triangle | P= side1 + side2 + side3 |
| ⬠ | Regular n-polygon | P= n × side |
| ⏢ | Trapezoid | P= base1 + base2 + side1 +side2 |
| ⬭ | Ellipse | 4 × radius1 × E(k,pi/2) E(k,pi/2) is the complete elliptic integral of the second kind k = (1/radius1) × sqrt(radius12 - radius22) |
Source: Spiegel, Murray R. Mathematical Handbook of Formulas and Tables.
Schaum's Outline series in Mathematics. McGraw-Hill Book Co., 1968.