Circumference, Area, and Volume - Basic Mathematics for Water and Wastewater Operators - page 162

■ Example 11.3
Problem: What is the perimeter of a rectangular field if its length is 100 ft and its
width is 50 ft?

Solution:

Perimeter = (2 × Length) + (2 × Width)

= (2 × 100 ft) + (2 × 50 ft) = 200 ft + 100 ft = 300 ft

■ Example 11.4
Problem: What is the perimeter of a square with 8-in. sides?

Solution:

Perimeter = (2 × Length) + (2 × Width)

= (2 × 8 in.) + (2 × 8 in.) = 16 in. + 16 in. = 32 in.

C irCuMferenCe
The circumference is the length of the outer border of a circle. The circumference is
found by multiplying pi (π) times the diameter ( D ) (a straight line passing through
the center of a circle, or the distance across the circle; see Figure 11.4):

C = π × D (11.2)

where
C = Circumference.
π = pi = 3.14.
D = Diameter.

Use this calculation if, for example, the circumference of a circular tank must be
determined.

D

FIGURE 11.4 Circumference.