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Lesson 7-4 Pages 304-308 Scale Drawings Lesson Check 7-3 What you will learn! How to solve problems involving scale drawings. Scale drawing Scale Scale factor Scale model What you really need to know! A scale drawing represents something that is too large or too small to be drawn at actual size. What you really need to know! A scale model can be used to represent something that is too large or too small for an actual-size model. What you really need to know! The scale gives the relationship between the drawing/model measure and the actual measure. Example 1: On the map, the distance between Portland and Olympia is about 1 7/8 inches. What is the actual distance? 3 7 in 1 in 3 7 m 1 x 25 8 8 8 8 25mi m From Lesson 6-5: Solving Equations involving Fractions! 3 m 46.875 7 8 m 46 8 8 3 125 miles Example 2: On the blueprint of a new house, onequarter inch represents 2 ½ feet. If the length of a bedroom on the blueprint is 1 ½ inches, what is the actual length of the room? 1 1 in 1 in 4 2 1 m 2 ft 2 1 1 1 m 1 x2 4 2 2 1 3 3 4 m3 m3 4 1 4 4 15 feet Example 3: Find the scale factor of a blueprint if the scale is ½ inch = 3 feet. 1 1 inch inch 2 2 3 feet 36inches 1 inch 2 1 inch 1 2 36inches 2 72inches 72 Example 4: A model is being created from a picture frame which has a width of 4 ¾ inches. If the scale to be used is 8 inches = 1 inch, what is the length of the model? Important Knowledge: Scales are always given with the real item as the denominator. 8 L 1 43 4 8 L 3 1 4 3 1 L 8 4 4 4 L 38 38 inches Page 306 Guided Practice #’s 3-8 Read: Pages 304-306 with someone at home and study examples! Homework: Page 307-308 #’s 9-15, 17-25, 28-38 Lesson Check 7-4 Page 581 Lesson 7-4 Lesson Check 7-4 Prepare for Mid-Test! Page 310 #’s 1-20 Lesson Check 7-4 Homework: Page 307-308 #’s 9-15, 17,18, 21-23, 28-38 Lesson Check 7-4 A rate is a ratio that compares quantities with different labels. A unit rate is a rate that is simplified so that the denominator is 1. Rate Unit Rate 225mi 3hrs 75mi 1hr A rate is a ratio that compares quantities with different units, such as 16feet/8seconds. A unit rate is a rate that is simplified so that it has a denominator of 1 unit, such as 2feet/1second. In a proportion, the cross product is the product of the numerator of one ratio and the denominator of the other ratio. In a proportion, a cross product is the product of the numerator of one ratio and the denominator of the other ratio. 8 2 12 3 8 x 3 = 24 12 x 2 = 24