- Length is a linear, or one dimensional measure
- Area is a two dimensional area.
- If we wanted to talk about the size of your desk, we would probably
talk about square inches.
- The chalkboard would be square feet
- The size of the room would probably be square feet, but perhaps square yards
- Houses are measured in square feet. I have a 1700 ft2 house.
- Land is measured in acre which corresponds to 43,560 ft2
- Land is also measured in square miles, PA is about 45,333 miles2
- Example: My property is 900ft x 500 ft, find the acreage
First calculate ft2
900 ft x 500 ft = 450,000 ft2
Calculate Acreage
1 Acre
450,000 ft2 x ----------- = 10.3 Acre
43,560 ft2
- Example 2, how many inch2 in a ft2
12 in
1 ft2 x ------ = 12 ft-in
ft
12 in
12 ft-in x ----- = 12x12 in2
ft
- Example: Acres in PA?
5280 ft 5280 ft 1 acre
45,333 miles2 x --------- x --------- x --------
1 mile 1 mile 43,560 ft2
= 45,333x5280x5280/43,560 acres
= 29,013,120 acres
- Population density is measured in people per mile2
- See number 34, page 478
population density = people/miles2
2,269789 people/147,046 miles2 = 26.7 people/mile2
- In the metric system, land is measured in km2 as well as in hectares (ha).
- 1 acre = .4 ha
- Volume is measured in cubic units.
- A cubic inch is 1in × 1in × 1in
- A cubic centimeter (cc) is 1cm × 1cm × 1cm
- Example: How many cc in a cubic meter?
100 cm 100 cm 100 cm
1 m3 x ------ x ------ x ------ = 1,000,000 cm3
1 m 1 m 1 m
- A second measure of volume is capacity
- We measure capacity in gallons, but also in liters (l)
- 231 in3 = 1 gallon
- 1 m 3 = 1kl
- Other units of capacity in the US Customary are: pints, quarts, cups, ounces, tablespoons, teaspoons, ...
- Each has a yuck-o conversion factor.
- Other units in the metric system are ml, cl, dl, dal, hl, kl