1. EXAMPLE 4 Use a scale drawing SOLUTION Maps The scale of the map at the right is 1 inch : 26 miles. Find the actual distance from Pocahontas to Algona. Use a ruler. The distance from Pocahontas to Algona on the map is about 1.25 inches. Let x be the actual distance in miles.

2. EXAMPLE 4 Use a scale drawing Cross Products Property Simplify. = 1.25 (26) x x = 32.5 The actual distance from Pocahontas to Algona is about 32.5 miles. 1.25 in. x mi 26 mi 1 in. = distance on map actual distance

3. EXAMPLE 5 Solve a multi-step problem What is the diameter of the actual dome? a. b. About how many times as tall as your model is the actual building? Scale Model You buy a 3-D scale model of the Reunion Tower in Dallas, TX. The actual building is 560 feet tall. Your model is 10 inches tall, and the diameter of the dome on your scale model is about 2.1 inches.

4. EXAMPLE 5 Solve a multi-step problem Cross Products Property measurement on model measurement on actual building = 1176 10 x x = 117.6 SOLUTION 10 in. 560 ft x ft 2.1 in. = a. Solve for x. The diameter of the actual dome is about 118 feet. ANSWER

5. EXAMPLE 5 Solve a multi-step problem b. To simplify a ratio with unlike units, multiply by a conversion factor. 560 ft 10 in. = 672 The actual building is 672 times as tall as the model. ANSWER 1 ft 12 in. 560 ft 10 in. =

6. GUIDED PRACTICE for Examples 4 and 5 4. Two cities are 96 miles from each other. The cities are 4 inches apart on a map. Find the scale of the map. SOLUTION The distance between two cities are 96 miles, and the distance on the map is 4 inches distance on map actual distance 96 mi 4 in = = 1 24 Simplify. = 1 : 24

7. GUIDED PRACTICE for Examples 4 and 5 ANSWER Scale of the map is 1 : 24 = 1 in : 24 mi

8. GUIDED PRACTICE for Examples 4 and 5 5. What If ? Your friend has a model of the Reunion Tower that is 14 inches tall. What is the diameter of the dome on your friend’s model? = 1646.4 560 x x = 2.94 SOLUTION 14 in. 560 ft 117.6 ft x in. = a. ANSWER 2.94 in. Cross Products Property measurement on model measurement on actual building Solve for x.