The base of a shape like a polygon is the bottom of the shape. In order to find the area of the base the formula one uses depends on the shape of the object. Here is a list of the most common base area formulas.
Formulas for finding the Area of Base of Geometric Shapes
| Triangle | 1⁄2 b*h b=base h=height b=base h =height |
| Rectangle | length * width |
| Trapezoid | 1⁄2 h ( b_1+ b_2 ) h = height b_1=base 1 b_2=base 2 |
| Square | s^2 s =side |
| Parallelogram | base * altitude |
| Pentagon | 1⁄2 a*p a = apothem P = perimeter |
| Hexagon | 1⁄2 a*p a = apothem P = perimeter |
| Heptagon | 1⁄2 a*p a = apothem P = perimeter |
| Octagon | 1⁄2 a*p a = apothem P = perimeter |
