In a scale drawing, all lengths are proportional to their corresponding actual lengths. The scale is the ratio that compares each length in the scale drawing to the actual length. The lengths used in a scale can be in different units. For example, a scale might be written as 1 cm to 50 km,
You can use proportions to find the actual dimensions represented in a scale drawing.
Problem 5 Using a Scale Drawing
Design The diagram shows a scale drawing of the Golden Gate Bridge in San Francisco. The distance between the two towers is the main span. What is the actual length of the main span of the bridge?
The length of the main span in the scale drawing is 6.4 cm. Let s represent the main span of the bridge. Use the scale to set up a proportion.
The actual length of the main span of the bridge is 1280 m.
Think
Why is it helpful to use a scale in different units?
1 cm : 200 m in the same units would be 1 cm : 20,000 cm. When solving the problem,
✓ Got It?
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- Use the scale drawing in Problem 5. What is the actual height of the towers above the roadway?
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Reasoning The Space Needle in Seattle is 605 ft tall. A classmate wants to make a scale drawing of the Space Needle on an
Table of Contents
- 6-1 The Polygon Angle-Sum Theorems
- 6-2 Properties of Parallelograms
- 6-3 Proving That a Quadrilateral Is a Parallelogram
- 6-4 Properties of Rhombuses, Rectangles, and Squares
- 6-5 Conditions for Rhombuses, Rectangles, and Squares
- 6-6 Trapezoids and Kites
- 6-7 Polygons in the Coordinate Plane
- 6-8 and 6-9 Coordinate Geometry and Coordinate Proofs