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SCIENCE. As part of an environmental study, you need to estimate the number of trees in a 150 acre area. You count 270 trees in a 2 acre area and you notice that the trees seem to be evenly distributed. Estimate the total number of trees. EXAMPLE 5. Solve a real-world problem. SOLUTION.
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SCIENCE As part of an environmental study, you need to estimate the number of trees in a 150 acre area. You count 270 trees in a 2 acre area and you notice that the trees seem to be evenly distributed. Estimate the total number of trees. EXAMPLE 5 Solve a real-world problem SOLUTION Write and solve a proportion involving two ratios that compare the number of trees with the area of the land.
n number of trees = 150 area in acres 270 150 = 20,250 270 n = 2 2 n EXAMPLE 5 Solve a real-world problem Write proportion. Cross Products Property Simplify. There are about 20,250 trees in the 150 acre area.
= ab x 2448 = 24 24 2 = = 24 2 The geometric mean of 24 and 48 is 2433.9. 2 EXAMPLE 6 Find a geometric mean Find the geometric mean of 24 and 48. SOLUTION Definition of geometric mean Substitute 24 for a and 48 for b. Factor. Simplify.
n number of trees 8. WHAT IF ?In Example 5, suppose you count 390 trees in a 3 acre area of the 150 acre area. Make a new estimate of the total number of trees. 150 area in acres 390 150 = 390 3 = 3 n 19,500 n = for Examples 5 and 6 GUIDED PRACTICE SOLUTION Write and solve a proportion involving two ratios that compare the number of trees with the area of the land. Write proportion. Cross Products Property Simplify.
ANSWER There are about19,500in the150acre area for Examples 5 and 6 GUIDED PRACTICE
ab = x 12 27 = 12 3 9 = = 18 for Examples 5 and 6 GUIDED PRACTICE Find the geometric mean of the two numbers. 9.12 and 27 SOLUTION Definition of geometric mean Substitute 12 for a and 27 for b. Factor. Simplify. The geometric mean of 12 and 27 is 18
ab = x 18 54 = 18 18 3 = = 18 3 The geometric mean of 18 and 54 is 18 3 for Examples 5 and 6 GUIDED PRACTICE Find the geometric mean of the two numbers. 10.18 and 54 SOLUTION Definition of geometric mean Substitute 18 for a and 54 for b. Factor. Simplify.
ab = x 16 18 = 16 9 2 = = 12 2 The geometric mean of 16 and 18 is 12 2 for Examples 5 and 6 GUIDED PRACTICE Find the geometric mean of the two numbers. 11.16 and 18 SOLUTION Definition of geometric mean Substitute 16 for a and 18 for b. Factor. Simplify.