The measurement of a two-dimensional region enclosed by a polygonal chain.

### Formulas

The following formulas can be used to find the area *A* of some common polygons:

Area of a square | A = s\(^2\) |
s: length of one side |

Area of a rhombus | A = \(\frac {d\space ×\space D}{2}\) |
d: length of the shorter diagonalD: length of the longer diagonal |

Area of a parallelogram | A = b × h |
b: baseh: height |

Area of rectangle | A = b × h |
b: baseh: height |

Area of a triangle | A = \(\frac{b\space ×\space{h}}{2}\) |
b: baseh: height |

Area of a trapezoid | A = \(\frac{(b\space+\space{B})\space×\space{h}}{2}\) |
b: shorter baseB: longer baseh: height |

Area of a regular convex polygon | A = \(\frac{a\space×\space{P}}{2}\) |
s: length of a sidea: slant heightn: number of sidesP: perimeter (P = ns) |