Perimeter and Area

Perimeter

Perimeter is the distance around a shape. Add all the side lengths.

Rectangle Perimeter

$P = 2l + 2w$ or $P = 2(l + w)$

where $l$ = length and $w$ = width

Square Perimeter

$P = 4s$

where $s$ = side length

Area

Area is the amount of space inside a shape (measured in square units).

Rectangle Area

$A = l \times w$

Square Area

$A = s^2$

Triangle Area

$A = \frac{1}{2}bh$

where $b$ = base and $h$ = height

Units

• Perimeter: linear units (cm, m, in, ft)
• Area: square units (cm², m², in², ft²)