Scale Factors and Percentages

This lesson introduces the concept of scale factor, explaining how it is used to increase or decrease the size of an object. It covers different ways to express scale factors, such as decimals, percentages, fractions, and ratios. The lesson also provides examples and exercises to convert between these forms. Additionally, it demonstrates how to calculate scale factors using ratios and apply them to solve real-world problems, such as determining dimensions of enlarged or reduced images.

What is a scale factor?

• A number used to add to a measurement

• A number used to subtract from a measurement

• A number used to divide a measurement

• A number used to multiply a measurement to change its size

If a large triangle is three times bigger than a smaller triangle, what scale factor was applied?

• 1

• 3

• 2

• 1/3

How can a scale factor be represented?

• Only as a ratio

• As a decimal, percent, fraction, or ratio

• Only as a fraction

• Only as a decimal

What does a scale factor of 0.2 indicate?

• An enlargement

• A doubling

• A reduction

• No change

Convert 0.7 to a percentage.

• 70%

• 700%

• 7%

• 0.7%

What is the ratio equivalent of 0.7?

• 7:10

• 10:7

• 3:2

• 1:1

If a scale factor is 1, what does it mean for the image?

• The image is enlarged

• The image is inverted

• The image is reduced

• The image remains unchanged

What is the fraction form of 425%?

• 17/4

• 4/25

• 425/100

• 25/4

How do you calculate the scale factor for a regular pentagon?

• Add the side lengths

• Multiply the side lengths

• Subtract the side lengths

• Divide the new side length by the original side length

What does a scale factor greater than 1 indicate?

• A reduction

• A reflection

• An enlargement

• No change