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Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
Algebra 1. 9.12 Lesson. Proportions
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Algebra 1. 9.12 Lesson. Proportions

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Algebra 1: Proportions

Algebra 1: Proportions

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  • 1. Bellringer: Solve each equation. 1. | x | = -6 2.  1 + | x  5| = 1 3. 2| x + 1| = 16 4. No Solutions 15 y 30 10 7, 3 5 = 7, -9
  • 2.
    • Bellringer
    • 3 Minutes to work on Friday WS
    • Rates, Ratios, & Proportions Practice
    • Group Quiz
    • Talk about project for this week
    Holt McDougal Algebra 1 2-7 Rates, Ratios, and Proportions Holt Algebra 1
  • 3. You have 3 minutes to work on WS from Friday – ask questions if needed.
  • 4. Write and use ratios, rates, and unit rates. Write and solve proportions. Objectives
  • 5. Proportion ? Rate ?
  • 6. In the proportion , the products a • d and b • c are called cross products . You can solve a proportion for a missing value by using the Cross Products property. Cross Products Property In a proportion, cross products are equal. WORDS NUMBERS ALGEBRA 2 • 6 = 3 • 4 If and b ≠ 0 and d ≠ 0 then ad = bc .
  • 7. Example 4: Solving Proportions Solve each proportion. Use cross products. Divide both sides by 3. Use cross products. A. B. Add 6 to both sides. Divide both sides by 2. 3( m ) = 5(9) 3 m = 45 m = 15 6(7) = 2( y – 3) 42 = 2 y – 6 +6 +6 48 = 2 y 24 = y
  • 8. Check It Out! Example 4 Solve each proportion. A. B. Use cross products. Divide both sides by 2. Use cross products. Subtract 12 from both sides. Divide both sides by 4. y = −20 – 12 –12 4 g = 23 g = 5.75 2 y = –40 2( y ) = –5(8) 4( g +3) = 5(7) 4 g +12 = 35
  • 9. More examples…
    • 3 gallons of paint cover 900 square feet. How many gallons will cover 300 square feet?
    3 x 900 300 = 900 = 900x 1 = x 1 gallons of paint will cover 300 square feet.
  • 10. More examples…
    • Making 5 apple pies requires 2 pounds of apples. How many pounds of apples are needed to make 8 pies?
    5 8 2 x = 16 = 5x 3.2 = x 3.2 pounds of apples are need to make 8 pies
  • 11. More examples…
    • Tony can run 10 blocks in 4 minutes. How long does it take him to run 15 blocks, at the same speed.
    10 15 4 x = 60 = 10x 6 = x It will take Tony 6 minutes to run 15 blocks
  • 12. Check It Out! Example 2 Cory earns $89.50 in 8 hours. Find the unit rate. The unit rate is $11.19 per hour. -Cory earns $11.19 per hour. 89.5 = 8 x 89.5 x 8 1 = 11.19 = x
  • 13. The ratio of games won to games lost for the Miami Heat basketball team is 3:2. The team has won 18 games. How many games did the team lose? Check It Out! Example 1 The team lost 12 games.
  • 14. Example 2: Finding Unit Rates Raulf Laue of Germany flipped a pancake 416 times in 120 seconds to set the world record. Find the unit rate. Round your answer to the nearest hundredth. The unit rate is about 3.47 flips/s.
  • 15. Check It Out! Example 2 Cory earns $52.50 in 7 hours. Find the unit rate. The unit rate is $7.50. Write a proportion to find an equivalent ratio with a second quantity of 1. Divide on the left side to find x. 7.5 = x
  • 16. Example 5A: Scale Drawings and Scale Models A contractor has a blueprint for a house drawn to the scale 1 in: 3 ft. A wall on the blueprint is 6.5 inches long. How long is the actual wall? x • 1 = 3(6.5) x = 19.5 The actual length of the wall is 19.5 feet. Write the scale as a fraction. Let x be the actual length. Use the cross products to solve. blueprint 1 in. actual 3 ft.
  • 17. Group Quiz: Part 1 1. In a school, the ratio of boys to girls is 4:3. There are 216 boys. How many girls are there? 162 2. Nuts cost $10.75 for 3 pounds. Find the unit rate in dollars per pound. $3.58/lb 3. 4. A scale model of a car is 9 inches long. The scale is 1:18. How many inches long is the car it represents? 16 162 in.
  • 18. Mini-Worksheet Discuss Project

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