Exploring Scale Factor in Geometry

Mr. Kou from the PHS Math Department provides a refresher on scale factors, explaining how to calculate and use them. He defines scale factor as the ratio of corresponding lengths in similar geometric figures and illustrates this with examples, including a Ferrari model, Van Gogh's Starry Night, and a doghouse enlargement. The video covers the concept of similar figures, where corresponding angles are congruent and side lengths are proportional, and demonstrates practical applications of scale factors in resizing objects.

What is a scale factor primarily defined as?

• A type of mathematical operation

• The ratio of corresponding lengths in similar figures

• A method to calculate area

• A formula for determining volume

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CCSS.7.G.A.1

In the context of scale factor, what does 'corresponding lengths' refer to?

• Matching lengths in similar figures

• Lengths that are unrelated

• Randomly chosen lengths

• Lengths that are equal in all respects

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What property do similar geometric figures share?

• Equal perimeters

• Identical colors

• Same texture

• Congruent corresponding angles

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CCSS.8.G.A.2

CCSS.HSG.CO.B.6

If a real Ferrari is 12 times the size of its model, what is the scale factor from the model to the real Ferrari?

• 1/12

• 24

• 1/24

• 12

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CCSS.7.G.A.1

What does it mean if two geometric figures are similar?

• They have the same color

• They cannot be compared

• They are of the same size

• Their corresponding angles are congruent and side lengths are proportional

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CCSS.8.G.A.2

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How can scale factor be visually represented using the example of a car?

• By comparing the size of a real car to its model

• By comparing the car's color intensity

• By comparing the car's speed

• By comparing the car's brand

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CCSS.7.G.A.1

How wide would Van Gogh's Starry Night be if resized to fit a 5 cm tall credit card?

• 6.31 cm

• 92 cm

• 73 cm

• 5 cm

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CCSS.7.G.A.1

What mathematical method is used to find the width of a resized painting?

• Division

• Addition

• Subtraction

• Cross multiplication

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CCSS.7.G.A.1

What is the width of the enlarged doghouse if the original was 1.5 m and the scale factor is 2 to 5?

• 3.75 m

• 7.5 m

• 2.5 m

• 1.5 m

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CCSS.7.G.A.1

What is the result of resizing the width of the original doghouse by a scale factor of 2 to 5?

• 5 m

• 0.6 m

• 3.75 m

• 2.5 m

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CCSS.7.G.A.1