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Scale Drawings Scale – The ratio that compares the measurements of the real object and its model. EX: 1 in = 6 ft Scale factor – written as a ratio without measurements and in simplest form EX: the scale factor of 1 in = 6 ft is 1/72 Identify the scale factor. Length (in.) Actual 12 Model 2 Wing span (in.) 18 3 EX1) model length actual length EX2) = 2 12 Write a ratio using one of the dimensions. = 1 6 Simplify. The scale is 1 inch = 3 feet. What is the scale factor? 1 inch = 1 inch 36 inches 3 feet = 1 36 To eliminate units convert 3 feet to inches. Conversion factor is 1 foot = 12 inches EX3) Find the Scale Factor from the following shape small large Model original small original Model large 3 3 12 12 Model = Original 3 Model 12 = Original 1 Scale factor = 4 Scale factor = 12 3 4 1 EX4) A photograph was enlarged and made into a poster. The poster is 20.5 inches by 36 inches. The scale factor is 5 . Find the size of the photograph. 1. Draw a picture. poster 20.5 photo w l 36 Think: 2. Write a proportion to find the length l and width w. 3. Solve the proportion. poster = 5 = 36 l photo 1 poster = 5 = 20.5 w photo 1 36 X 1= 36 20.5 X 1= 20.5 36 ÷ 5 = 7.2 20.5 ÷ 5 = 4.1 Notes start here assignment Page 313 Problems 1-6 Date _______ Scaling Drawings Scale – The ratio that compares the _________________ of the _____ object and its _______. EX: 1 in = 6 ft Scale _______ – written as a ratio _______ measurements and in ________________ EX: the scale factor of 1 in = 6 ft is _______ Identify the scale factor. EX1) Actual Model Length (in.) Wing span (in.) model length actual length EX2) = Write a ratio using one of the dimensions. = Simplify. The scale is 1 inch = 3 feet. What is the scale factor? 1 inch = 3 feet = To eliminate units convert 3 feet to inches. Conversion factor is __________________ EX3) Find the Scale Factor from the following shape small large Model original small original Model large 3 3 12 12 Model = Original Scale factor = Model = Original Scale factor = EX4) A photograph was enlarged and made into a poster. The poster is 20.5 inches by 36 inches. 5 The scale factor is 1. Find the size of the photograph. 1. 2. 3. Think: poster photo