McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
8. Dilations
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Exercise 20 Page 698

Start by converting between millimeters and centimeters.

96, see solution.

Practice makes perfect

A microscope is used to enlarge tiny objects. Under a microscope, 0.5-millimeters-long spider mite appears 4.8-centimeters-long. We want to find the scale factor k of the enlargement. Before we do that, we should first convert 4.8 centimeters to millimeters.

Converting Units

We know that 10 millimeters are equal to 1 centimeter. 10 mm = 1 cm To convert between units, we multiply by the conversion factor. It is a ratio of two equal lengths expressed using different units. Here the conversion factor is 10 mm 1 cm. Let's then multiply 3.75 centimeters by this factor and simplify. 4.8 cm * 10 mm/1 cm = 48 mm We found that 4.8 centimeters is 48 millimeters.

Scale Factor

Now we can find the scale factor k. It is the ratio of the length of the image and the corresponding length of the preimage. k=image length/preimage length We know that the actual length of the insect is 0.5 mm and that the corresponding length under the microscope is 4.8 cm, or 48 mm. Let's substitute these lengths into the formula and evaluate the expression.
k=image length/preimage length
k=48/0.5
k=96
The scale factor is 96.