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Section 2

1. Section 2

1.38. Explore 2

Mathematics 20-3 Module 5

Section 2: Perspective and Scale

 

Self-Check 1
  1. A map is drawn to a scale of 1:250 000. How many miles does 1 in on the map represent? Remember, there are 5280 ft in a mile. Round your answer to the nearest tenth of a mile. Answer

There are instances when a drawing or model is larger than the original. This is called a magnification. Microscope images, pictures, and diagrams are examples. When magnifying, the scale is greater than 1. For example, if the width of a scale drawing is 40 times the original, the scale would be 40:1 or .

 

Did You Know?

This is a photo of a woman looking through a microscope.

Hemera/Thinkstock

In order to determine the scale factor of the image viewed through a microscope, you must multiply the magnification for the ocular lens by the magnification of the objective lens.


 

 

Example

 

This thumbnail opens the Amoeba video.
istockphoto/Thinkstock

An amoeba is a tiny, one-celled organism frequently studied by biologists. You need a microscope to see most amoebas: the largest are only about 1 mm across. If an amoeba measuring 0.32 mm is observed through a microscope at 40x magnification, what size will its magnified image be?

 

If you are interested in learning more about amoebas, watch the video “Inside an Amoeba.”

 

Solution

 

  1. Write 40x magnification as a ratio.
 → 40:1 = magnified image size:actual object size
  1. Set up a proportion to find the magnified image size.
 →
  1. Solve for x.
 →

 

The size of the amoeba through the microscope would be 12.8 mm.