January 28, 2010 Math 201 OBJECTIVE: Students will be able to solve simple proportions. AIM: How is solving a proportion the same as finding an equivalent fraction? STANDARDS: 6.A.5 PRIOR KNOWLEDGE: Which of these are equivalent fractions?

Proportions always have an equal sign! MINI LESSON: A proportion is an equation where a pair of ratios are equivalent. They can include different units of measurement (like hours, feet, pounds, etc.) Proportions always have an equal sign! In simple proportions, all you need to do is examine the fractions. If the fractions simplify to the same value, then the proportion is true 4/6 = 8/12 is a true proportion because 4/6 simplifies to 2/3 and 8/12 simplifies to 2/3

In simple proportion problems, we are asked to find the missing number that makes the proportion true Example: Briana charges $8.00 for every hour she babysits. How many hours will it take for her to earn $24.00? Step 1 Write the ratio of different units Step 2 Use h to stand for the missing hours we need to find

8 1 Write the ratios as a proportion: dollars hours Make a table to help find h and skip count to 24 dollars 8 hours 1

ANSWER So it will take Briana _________ hours to make $24.00 EXAMPLE 2 John can shovel 10 driveways in 4 hours. How many driveways can he shovel in 12 hours? (Use the letter d to stand for the missing number of driveways you need to find) Step 1 Write the ratio of different units

10 4 Step 2 Write the proportion Now use a table to find the missing number driveways 10 hours 4 John can shovel __________ driveways in 12 hours

INDEPENDENT PRACTICE Problem Compact disks are on sale for a price of 3 for $20. How many CDs can be bought for $80?

Problem For every 5 peanuts that Richie ate, Tiesha ate 9 peanuts. If Richie ate a total of 30 peanuts, how many peanuts did Tiesha eat? HOMEWORK #3.4: Handout