Glencoe Math: Course 3, Volume 2
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Glencoe Math: Course 3, Volume 2 View details
5. Similar Triangles and Indirect Measurement
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Exercise 7 Page 557

We are given the following situation and we want to find the height of the nearby man.

ferris wheel

We can see that this is a shadow problem. We can assume that the angles formed by the sunbeams when the objects are hit by the light are congruent. The two shapes that are created by the sunbeams are right triangles.

congruent angles
If we think about the ground as a transversal and the sunbeams as parallel lines, then the angles created are corresponding angles. Since two pairs of corresponding angles are congruent, the above triangles are similar by the Angle-Angle (AA) Similarity rule. This means that the ratio of the heights of the Giant Wheel and the man will be equal to the ratio of the lengths of their shadows.
Let's solve this proportion using cross products.
Solve for
The man is feet tall.