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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

7. Scale Drawings and Models

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Exercise 30 Page 605

Evaluate a ratio of widths and a ratio of lengths. Are they the same?

Is it a dilation? Yes.
Scale factor: 4

Practice makes perfect

We are asked to determine if the painting a dilation of the original photo. To do this, we will compare a ratio of widths and a ratio of lengths. If they turn out to be equal, then we have a dilation. Painting Width/Photo Width? =Painting Length/Photo Length Let's evaluate these ratios using the given dimensions. We will start with the ratio of widths.

Painting Width/Photo Width

Painting Width= 24, Photo Width= 6

24/6

Calculate quotient

4

The ratio of widths is 4. Now, we will evaluate the ratio of lengths.

Painting Length/Photo Length

Painting Length= 32, Photo Length= 8

32/8

Calculate quotient

4

The ratio of lengths is also 4. Painting Width/Photo Width? =Painting Length/Photo Length ⇓ 4=4 Since the ratios are equal, the painting is a dilation of the original photo, and the scale factor is 4.

Subchapter links

Exercises p.602-605