Circumference, Area, and Volume - Basic Mathematics for Water and Wastewater Operators - page 161

PERIMETER AND CIRCUMFERENCE
On occasion, it may be necessary to determine the distance around grounds or land-
scapes. To measure the distance around property, buildings, and basin-like struc-
tures, it is necessary to determine either perimeter or circumference. The perimeter
is the distance around an object; it is the border or outer boundary. Circumference
is the distance around a circle or circular object, such as a clarifier. Distance is a
linear measurement that defines the distance (or length) along a line. Standard units
of measurement such as inches, feet, yards, and miles and metric units such as cen-
timeters, meters, and kilometers are used.

p eriMeter
The perimeter ( P ) of a rectangle (a four-sided figure with four right angles) is obtained
by adding the lengths ( L i ) of the four sides (see Figure 11.2):

Perimeter = L 1 + L 2 + L 3 + L 4 (11.1)

■ Example 11.2
Problem: Find the perimeter of the rectangle shown in Figure 11.3.

Solution:

Perimeter = 35 ft + 8 ft + 35 ft + 8 ft = 86 ft

L 1

L 4 L 2

L 3

FIGURE 11.2 Perimeter.

35 ft

8 ft 8 ft

35 ft

FIGURE 11.3 Perimeter of a rectangle for Example 11.2.