8.1 Ratio and Proportion

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March 28, 2016

Warm Up

1m = ____ cm

1km = ____ m

Fill in the following conversions.

1mi = _____ ft

1 ft = ____ in.

1 yd = ____ ft 1lb = ____ oz

1cm = ____ mm

1kg = ____ g

8.1 Ratio and ProportionGoals: • Find and simplify the ratio of two numbers

• Use proportions to solve real­life problems

EQ: How do you set up ratios and proportions?

Vocabulary

Ratio of a to b: compares 2 quantities by divisionCan be written in 3 forms:

*both need to be in same units

*since it's a quotient, b = 0*simplify when possible

Proportion: equation that states 2 ratios are equal

Extremes:

Means:

Example 1: Simplifying RatiosSimplify the ratio.

a. b.

8.1 Ratio and Proportion

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March 28, 2016

Example 2: Using RatiosThe perimeter of rectangle JKLM is 56 centimeters. The ratio of JK:KL is 4:3. Find the length and width of the rectangle.

Try It1. The area of rectangle JKLM is 540 inches. The ratio of JK:KL is 3:5. Find the length and width of the rectangle.

Simplify the ratio.2. 3.

Example 3: Solving Proportions

Example 4: Solving a ProportionA scale model of a car is 10 inches long and 5 inches tall. The actual car is 60 inches tall. What is the length of the actual car?

10 in.

5 in.

"model car" "actual car"

60 in.

?

Try It Solve the proportion.

4. 5.

8.1 Ratio and Proportion

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March 28, 2016

SummaryEQ: How do you set up ratios and proportions?

8.1 Homeworkp.461#10­46e, 51­53, 54­58e, 68­75

*Ch.6 Test­Out of 44

­Needed 29+ for 65%