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Ratios and Rates A ratio is a comparison of two numbers by division. A rate represents quantities measured in different units. $ 1.50 for 16 ounces of.

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Presentation on theme: "Ratios and Rates A ratio is a comparison of two numbers by division. A rate represents quantities measured in different units. $ 1.50 for 16 ounces of."— Presentation transcript:

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2 Ratios and Rates A ratio is a comparison of two numbers by division. A rate represents quantities measured in different units. $ 1.50 for 16 ounces of soda A unit rate is a rate with a denominator of 1. Division is used to find a unit rate. That sounds pretty easy.

3 Finding Unit Rates The following table gives prices for different sizes of apple juice. Find the unit rate for each. Which has the lowest cost per ounce? The 64 ounce bottle has the lowest cost per ounce. In 2004, Lance Armstrong won the Tour de France, completing the 3391 km course in 83.6 hours. Find his average speed.

4 Converting Rates A runner runs 4 miles in 45 minutes. What is his average speed in miles per hour? A cheetah ran 300 feet in 2.92 seconds. What was the cheetah’s average speed in miles per hour? The cheetah’s average speed in miles per hour is approximately 70 MPH Asi de facil

5 Converting Units Convert the given amount to the given unit. There’s a table on page 814 that can help. 330 mins; hours 60 minutes = 1 hour 15kg; grams 1 kg = 1,000 grams 5 ft 3 in; inches 12 inches = 1 foot 1,250 cm; meters 100 cm = 1 meter That was easy

6 Converting Units Between Systems Convert the given amount to the given unit. There’s a table on page 814 that can help. 9 yds; meters 1 yd = 3 ft : 1 ft =.305 m 5 qt; liters 1 qt =.946 L 89 cm; inches 1 in = 2.54 cm 7 kg; pounds 1 lb =.454 kg Asi de Facil

7 Homework Page 119: 12 - 30 Even Numbers

8 Solving Proportions A Proportion is an equation that states that two ratios are equal. Solve each proportion using the Multiplication Property.

9 Solving Proportions Using the Cross Products Property Solve each proportion using the Cross Products Property.

10 Solving Multi-Step Proportions Asi de Facil

11 Proportions Word Problems Proportions are written as ratios. You drive 50 miles in 35 minutes. How long would it take you to drive 70 miles at the same rate of speed? It would take 49 minutes to drive 70 miles. A box of cereal weighing 354 grams contains 20 grams of fat. Find the number of grams of fat in the recommended serving size of 55 grams. A 55 gram serving contains approximately 3.1 grams of fat.

12 Homework Page 127: 10 – 36 Even Numbers

13 Similar Triangles Similar Triangles are the same shape but not necessarily the same size. In Similar Triangles corresponding angles are congruent and corresponding sides are in proportion. A B CD E F Let’s throw some numbers in there. 12 15 18 8 10 12

14 Similar Triangle Examples The figures in each pair are similar. Find the missing length. 4 8 10 x 15 6 20 x 10 16 x 13 7 9 11 x 18 3.75 27 Asi de facil x

15 Applying Similarity A tree casts a shadow 7.5 feet long. A 5 foot tall woman casts a shadow 3 feet long. How tall is the tree? 7.53 5 x The tree is 12.5 feet tall. A 60 foot tall building casts a shadow 22 feet long. A brick 15 foot wall is next the building. How long is the shadow that the wall casts? 60 22 15 x The shadow is 5.5 feet long.

16 Maps and Scale Drawings The scale on a map is 1 inch : 32.5 miles. Find the following actual distances. 3 inches 4.5 inches 13.25 inches An architect's drawing is in the scale 1 inch : 6 feet. What are the actual dimensions of a room that is 3.5 inches by 2.5 inches on the drawing? The room is 21 feet by 15 feet. What would the measurements on the drawing be for a room that is 30 feet by 24 feet? On the drawing the room would be 5 inches by 4 inches.

17 Homework Page 134: 6 – 18 Even Numbers Page 135: 19 – 21 All Questions


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