# Area

quantity that expresses the extent of a two-dimensional surface or shape, or planar lamina, in the plane

Area is the amount of space a two dimensional (flat) surface takes up. It is useful because it is how much of a material is needed to make a hollow container. Area is the amount of surface covered by a close object or shape.

Some units used to measure area are square foot, square mile, square metre and square kilometre. The area of a planar figure is often written as ${\displaystyle A}$.[1] Areas of regular shapes such as square, rectangle, triangle and circle can be calculated through formulas.[2] The area of an irregular shape can be approximated through grid or graph paper.[3]

One can use different formulas to find the area of different shapes. For example:[2]

• Area of a rectangle is the length of any two touching sides multiplied together. In other words, length times width.
• Area of a triangle is half of the base multiplied by the perpendicular height. In other words, ${\displaystyle A={\tfrac {1}{2}}bh}$.
• Area of a circle: ${\displaystyle A=\pi r^{2}}$

The area of a flat object is related to the surface area and volume of a three-dimensional object.

The area under a curve can be found using integration, a concept from calculus.

## References

1. "List of Geometry and Trigonometry Symbols". Math Vault. 2020-04-17. Retrieved 2020-09-24.
2. "Area - Math Open Reference". www.mathopenref.com. Retrieved 2020-09-24.
3. "What is Area?". www.mathsisfun.com. Retrieved 2020-09-24.