420 CHAPTER 7 The Metric System Units of Area in the Metric System In Chapter 8, we provide formulas and discuss procedures for determining the area and volume of many geometric figures. The procedures and formulas for determining area and volume are the same regardless of whether the units are metric units or customary units. The area enclosed in a square with 1-centimeter sides (Fig. 7.3) is × 1 cm 1 cm = 1 cm .2 A square whose sides are 2 cm (Fig. 7.4) has an area of × 2 cm 2 cm = = 2 cm 4 cm . 2 2 2 1 cm 1 cm 1 cm 2 Figure 7.3 2 cm 2 cm 4 cm2 Figure 7.4 Areas are always expressed in square units, such as square centimeters, square kilometers, or square meters. When determining areas, the numbers being multiplied must be expressed in the same units. Areas measured with square inches are measured with square centimeters in the metric system. Areas measured with square feet or square yards are measured with square meters. In the metric system, a square that measures 100 meters by 100 meters is a square hectometer or a hectare (symbolized ha). A hectare is about 2.5 acres and is used to measure land areas. Very large areas are measured in square kilometers in the metric system. One square kilometer is about 4 10 square mile. One square kilometer is 100 hectares. Example 2 Choosing an Appropriate Unit of Area Determine which metric unit of area you would use to measure the area of the following. a) Shenandoah National Park b) The top of a kitchen table c) The floor of a classroom d) The screen of an iPad e) A football field f) An ice-skating rink g) A nickel h) A framed portrait Solution a) Square kilometers or hectares b) Square meters or square centimeters c) Square meters d) Square centimeters e) Hectares or square meters f) Square meters g) Square millimeters or square centimeters h) Square centimeters 7 Now try Exercise 25 AboutLife/Shutterstock
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