Calculating Area: Common Shape Formulas
Learn how to calculate area for rectangles, squares, triangles, and circles with simple formulas and examples.
Searching calculating area usually means you need the size of a surface. Area measures the amount of two-dimensional space inside a shape.
Common Area Formulas
| Shape | Formula |
|---|---|
| Rectangle | Length x Width |
| Square | Side x Side |
| Triangle | 1/2 x Base x Height |
| Circle | pi x r^2 |
Example: Rectangle
A rectangle that is 10 by 8 has:
10 x 8 = 80 square units
Example: Triangle
A triangle with base 12 and height 5 has:
1/2 x 12 x 5 = 30 square units
Example: Circle
A circle with radius 4 has:
pi x 4^2 = 16pi = about 50.27 square units
The Bottom Line
To calculate area, identify the shape and use the matching formula. Keep the units consistent, and remember that area is always expressed in square units.
How to Calculate: Step-by-Step Guide
Identify the shape
The formula depends on whether the shape is a rectangle, triangle, circle, or something else.
Measure needed dimensions
Use the correct base, height, radius, length, or width.
Apply the matching formula
Use the shape-specific formula and keep units consistent.