Area of a Rectangle
Area · Class IV
Count unit squares inside a rectangle.
7 u
type a value
120
4 u
type a value
120
Live values
- Area (sq units)28
- Perimeter (units)22
- Area as width varies
Formulas in this lab
- Area (sq units)
- Perimeter (units)
Tip: With length fixed, area grows as a straight line: every extra unit of width adds l more squares.
Frequently asked questions
▶What is the area of a rectangle?
Area is the space inside a shape, measured in square units. For a rectangle, area equals length times width. A 5 by 3 rectangle has area 15 square units.
▶How do I use the area lab?
Choose the length and width with sliders. The lab draws the rectangle and fills it with unit squares so you can count them. The final area is also written below.
▶When do we measure area?
Buying tiles for a room, a carpet for the hall, or paint for a wall all use area. A 4 m by 3 m room needs 12 square metres of flooring.
▶Quick area formula
Area of a rectangle equals length times width. So a 7 by 6 rectangle has area 42 square units. This shortcut works because each row has length unit squares, and there are width rows.