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EXAMPLE 2. Solving a Problem. Junior Iditarod Race. In the 2001 Junior Iditarod race, one team completed the race in about 18 hours over two days. The team’s average rate was 8.325 miles per hour. About how long was the race? Round to the nearest mile. EXAMPLE 2. Solving a Problem.
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EXAMPLE 2 Solving a Problem Junior Iditarod Race In the 2001 Junior Iditarod race, one team completed the race in about 18 hours over two days. The team’s average rate was 8.325 miles per hour. About how long was the race? Round to the nearest mile.
EXAMPLE 2 Solving a Problem SOLUTION Use the formula Distance = Rate Time
EXAMPLE 2 Solving a Problem SOLUTION Use the formula Distance = Rate Time 8.325 18
EXAMPLE 2 Solving a Problem SOLUTION Use the formula Distance = Rate Time 8.325 18 66600 8325 149.850 Place the decimal point before dropping any zeroes
EXAMPLE 2 Solving a Problem SOLUTION Use the formula Distance = Rate Time 8.325 18 66600 8325 149.850 Place the decimal point before dropping any zeroes ANSWER The race was about 150 miles long.
EXAMPLE 3 Checking for Reasonableness Use estimation to check that the answer to Example 2 is reasonable.
EXAMPLE 3 Checking for Reasonableness Use estimation to check that the answer to Example 2 is reasonable. Distance = 8.325 18
EXAMPLE 3 Checking for Reasonableness Use estimation to check that the answer to Example 2 is reasonable. Distance = 8.325 18 8 18 Round 8.325 to its leading digit.
EXAMPLE 3 Checking for Reasonableness Use estimation to check that the answer to Example 2 is reasonable. Distance = 8.325 18 8 18 Round 8.325 to its leading digit. = 144
EXAMPLE 3 Checking for Reasonableness Use estimation to check that the answer to Example 2 is reasonable. Distance = 8.325 18 8 18 Round 8.325 to its leading digit. = 144 ANSWER Because 150 is close to 144, the distance is reasonable.
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50 = 45
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50 = 45 6. 1.505 8
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50 = 45 6. 1.505 8 = 12.04
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50 = 45 6. 1.505 8 = 12.04 7. 3.14 75
for Example 2 and 3 GUIDED PRACTICE Find the product. 5. 0.9 50 = 45 6. 1.505 8 = 12.04 7. 3.14 75 = 235.5
for Example 2 and 3 GUIDED PRACTICE Bicycle Race You complete the first leg of a bike race in about 12 hours over two days. Your cyclometer shows that your average speed for this leg was 15.95 miles per hour. About how long was this leg of the race?
for Example 2 and 3 GUIDED PRACTICE Bicycle Race You complete the first leg of a bike race in about 12 hours over two days. Your cyclometer shows that your average speed for this leg was 15.95 miles per hour. About how long was this leg of the race? ANSWER About 192 miles
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572 The answer is reasonable.
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572 The answer is reasonable. 10. 12.706 3; 381.18
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572 The answer is reasonable. 10. 12.706 3; 381.18 The answer is not reasonable.
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572 The answer is reasonable. 10. 12.706 3; 381.18 The answer is not reasonable. 11. 15.312 4; 61.248
for Example 2 and 3 GUIDED PRACTICE Use estimation to check whether the answer is reasonable. 9. 3.254 18; 58.572 The answer is reasonable. 10. 12.706 3; 381.18 The answer is not reasonable. 11. 15.312 4; 61.248 The answer is reasonable.
for Example 2 and 3 GUIDED PRACTICE 12. Explain why the answer 84 is not reasonable for the product 3 2.8.