# 5.8 Scale Drawing and Models

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5.8 Scale Drawing and Models

Scale Drawing/Model Is used to represent an object that is too large or to small to be drawn or built to its actual size and is proportional to the actual.

Ratio of the model to the actual
Scale Ratio of the model to the actual

To Find Scale

Example 1 The length of a model of a bridge is 16 inches. The actual length of the bridge is 50 yards. What is the scale of the model? The scale is 1 in = yards

Meaning the actual is 24 times as big
Scale Factor When the scale drawing and model have the same unit of measure. Example: Scale: 1 inch = 2 feet Scale Factor: 1in : 24 in Meaning the actual is 24 times as big

The actual is 96 times the map length
Example 2: A map of a natural history museum shows that the dinosaur exhibit room is 7.25 inches wide. If the scale on the map is 1 inch = 8 feet, what is the width of the actual exhibit room? Method 1: Using Scale and Proportions Method 2: Using Scale Factor and Equations 1in = 8 feet The actual is 96 times the map length Let a= actual, m= map a=96m a=96(7.25) a=696 inches 58 feet

Example 3 Construct a Scale Drawing on Paper
An architect is designing a school courtyard that is 45 feet long and 30 feet wide. Make a scale drawing of the courtyard. Use a scale of 0.5 inch= 10 feet. Use ¼ inch graph paper. 0.5 inches = 2 boxes on the ¼ inch graph paper Length: 45/10= 4.5 of 2 boxes= 4.5 (2) = 9 boxes Width: 30/10=3 of 2 boxes= 3(2)= 6 boxes Draw it

Homework Page 227 (2-16) even