Scale Drawings

1
Scale Drawings Models

• Section 4.6

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Section 4.6 Scale Drawings Models

• Distances on a scale drawing or model are
  proportional to real-life distances. The scale
  is determined by the ratio of a length on a
  drawing or model to its corresponding actual
  length.

3
Examples

• The local school district has made a scale model
  of a campus of Engels Middle School including a
  proposed new building. The scale of the model is
  1 inch 3 feet.

New Building
Gym
Parking
Academic Building
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Example Continued

• An existing gym is 8 inches tall in the model.
  How tall is the actual gymnasium?

Set up a proportion
1 8 3 X
New Building
Gym

Parking
Academic Building
1(x) 3(8) X 24 feet tall
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Section 4.6

• To find the scale factor for scale drawings and
  models, write the ratio given by the scale in
  simplest form.
• Write the ratio of 1 inch to 1 feet in
  simplest form.
• 1 inch 1 in.
• 1 Feet 16 in.

1 3
Conversion 1 foot 12 inches

1 3
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Example
3 4

• On a map, two cities are 5 inches apart. The
  scale of the map is 0.5 inch 3 miles. What is
  the actual distance between the towns?

Set up a proportion.
3 4
0.5X 3(5 ) 0.5X 17.25 X 34.5 miles
3 4
0.5 inch 5 inch 3 miles X miles

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Example

• Marta is making a scale drawing of her apartment
  for a school project. The apartment is 28 feet
  wide. On her drawing, the apartment is 7 inches
  wide. What is the scale of Martas drawing?

Set up a proportion.
28 feet
28 feet 4 feet 7 inches 1 inch

1 inch 4 feet