| Form |
 |
Method
of Finding Areas |
 |
| Triangle |
 |
 |
 |
Base x 1/2 perpendicular height

s = 1/2 sum of the three sides a, b, c |
|
 |
| Trapezium |
 |
 |
 |
| Sum of area of the two triangles |
|
 |
| Trapezoid |
 |
 |
 |
| 1/2 sum of parallel sides x perpendicular
height |
|
 |
| Parallelogram |
 |
 |
 |
| Base x perpendicular height |
|
 |
| Regular
Polygon |
 |
 |
 |
| 1/2 sum of sides x inside radius |
|
 |
| Circle |
 |
 |
 |
| 0.7854 x diameter2 = 0.07958
x circumference2 |
|
 |
| Sector of
a Circle |
 |
 |
 |
=
0.0087266 r2Ao= arc x 1/2 radius |
|
 |
| Segment
of a Circle |
 |
 |
 |
|
 |
Circle
of same area as a square |
 |
 |
 |
| Diameter = side x 1.12838 |
|
 |
Square
of same area as circle |
 |
 |
 |
| Side = diameter x 0.88623 |
|
 |
| Ellipse |
 |
 |
 |
| Long diameter x short diameter
x 0.78540 |
|
 |
| Parabola |
 |
 |
 |
| Base x 2/3 perpendicular height |
|