Area

Area measures how much flat surface a shape covers. It is always reported in square units: a rectangle 3 units by 4 units has an area of 12 square units.

Area is found by decomposing or composing shapes:

• Rectangle: length × width
• Triangle: ½ × base × height
• A polygon can be split into triangles whose areas add up.

Area is two-dimensional. Its three-dimensional counterpart is volume, and the area of a solid's outer surface is its surface-area.