Area
The area of a plane figure, measured in square units(or units2), is the number of squares required to cover it completely.
Example:
The figure shown has an area of 9.5 square units: 8 whole squares plus 3 half-squares.
Here are some formulas for the areas of common plane figures.
Shape |
Formula |
Variables |
Square |
|
s is the length of the side of the square. |
Rectangle |
|
L and W are the lengths of the rectangle's sides (length and width). |
Triangle |
 |
b and h are the base and height . |
Triangle |
 |
a, b, and c are the side lengths and s is the semiperimeter |
Parallelogram |
|
b is the length of the base and h is the height. |
Trapezoid |
 |
b1 and b2 are the lengths of the parallel sides and h the distance (height) between the parallels. |
Circle |
A = πr2 |
r is the radius. |
