Perimeter
The perimeter of a polygon is the sum of the lengths of all its sides.
Example:
What is the perimeter of a rectangle having side-lengths of 3.4 cm and 8.2
cm? Since a rectangle has 4 sides, and the opposite sides of a rectangle have
the same length, a rectangle has 2 sides of length 3.4 cm, and 2 sides of length
8.2 cm. The sum of the lengths of all the sides of the rectangle is
3.4 + 3.4 + 8.2 + 8.2 = 23.2 cm.
Example:
What is the perimeter of a square having side-length 74 cm? Since a square
has 4 sides of equal length, the perimeter of the square is
74 + 74 + 74 + 74 = 4 × 74 = 296.