Lesson 7
Units in scaled drawings
Unit 2
Scale Drawings
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7.1 Warm Up: Think • Pair • Share - One to One Hundred
A map of a park says its scale is 1 to 100.
1. What do you think that means?
2. Give an example of how this scale could tell us about measurements in the park.
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Learning Targets
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7.2 Apollo Lunar Module
Your teacher will give you a drawing of the Apollo Lunar Module. It is drawn at a scale of 1 to 50.
1. The “legs” of the spacecraft are its landing gear. Use the drawing to estimate the actual length of each leg on the sides. Write your answer to the nearest 10 centimeters. Explain or show your reasoning.
2. Use the drawing to estimate the actual height of the Apollo Lunar Module to the nearest 10 centimeters. Explain or show your reasoning.
3. Neil Armstrong was 71 inches tall when he went to the surface of the Moon in the Apollo Lunar Module. How tall would he be in the drawing if he were drawn with his height to scale? Show your reasoning.
4. Sketch a stick figure to represent yourself standing next to the Apollo Lunar Module. Make sure the height of your stick figure is to scale. Show how you determined your height on the drawing.
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7.2 Are you ready for more?
The table shows the distance between the Sun and 8 planets in our solar system.
1. If you wanted to create a scale model
of the solar system that could fit
somewhere in your school, what
scale would you use?
2. The diameter of Earth is approximately
8,000 miles. What would the diameter
of Earth be in your scale model?
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7.3 The World’s Largest Flag
As of 2016, Tunisia holds the world record for the largest version of a national flag. It was almost as long as four soccer fields. The flag has a circle in the center, a crescent moon inside the circle, and a star inside the crescent moon.
1. Complete the table. Explain or show your reasoning.
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7.3 The World’s Largest Flag
2. Complete each scale with the value that makes it equivalent to the scale of 1 to 2,000. Explain or show your reasoning.
Part 3.
a. What is the area of the large flag?
b. What is the area of the smaller flag?
c. The area of the large flag is how many times the area of the smaller flag?
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Lesson Summary
Sometimes scales come with units, and sometimes they don’t. For example, a map of Nebraska may have a scale of 1 mm to 1 km. This means that each millimeter of distance on the map represents 1 kilometer of distance in Nebraska. The same scale without units is 1:1,000,000, which means that each unit of distance on the map represents 1,000,000 units of distance in Nebraska. This is true for any choice of unit.
A scale tells us how a length on a drawing corresponds to an actual length, and it also tells us how an area on a drawing corresponds to an actual area. For example, if 1 centimeter on a scale drawing represents 2 meters in actual distance, what does 1 square centimeter on the drawing represent in actual area? The square on the left shows a square with side lengths 1 cm, so its area is 1 square cm.
The square on the right shows the actual dimensions represented by the square on the left. Because each side length in the actual square is 2 m, the actual square has an area of 22 or 4 square meters.
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12.5 Cool Down: Drawing the Backyard
Lin and her brother each created a scale drawing of their backyard, but at different scales. Lin used a scale of 1 inch to 1 foot. Her brother used a scale of 1 inch to 1 yard.
1. Express the scales for the drawings without units.
2. Whose drawing is larger? How many times as large is it? Explain or show your
reasoning.
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Reflections
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Practice Problems
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Lesson Video
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