Trigonometry : Proportions in Similar Triangles

Study concepts, example questions & explanations for Trigonometry

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Example Questions

Example Question #2 : Similar Triangles

Which of the following shifts are incorrect?

Possible Answers:

Correct answer:

Explanation:

The actual shift for  is .

Example Question #36 : Triangles

A right triangle has side lengths of , , and . A similar right triangle has sides of , , and . What is

Possible Answers:

There is not enough information to determine. 

 

Correct answer:

 

Explanation:

Similar triangles by defnition have proportional sides. We can divide corresponding parts in this case to find the scale factor.

Corresponding parts are the two smallest sides, the medium sides, and the largest sides.

Thus: 

 is the scale factor. 

 Then, we use this to find the missing side. 

Therefore, .

 

 

Example Question #38 : Triangles

Corresponding sides of two triangles have measures of  and . If another side of the small triangle is , what is the value of the bigger triangles corresponding side? 

Possible Answers:

Correct answer:

Explanation:

We can find the scale factor by dividing 18 by 6.

We get that the scale factor is 3.

Multiplying the other side by 3, we get the new side, 21. 

Example Question #1 : Proportions In Similar Triangles

Which set of the following triangle dimensions does NOT have the same proportions as a 3-4-5 triangle?

Possible Answers:

Correct answer:

Explanation:

In order to determine whether if the dimensions of the triangle are of the same proportions, the ratios of the dimensions must also be the same as the 3-4-5 triangle.

The following scale factors multiplied to the 3-4-5 triangle yield similar proportions.

The only dimensions that cannot be attained by multiplying a particular scale factor with the 3-4-5 is:

Example Question #2 : Proportions In Similar Triangles

These triangles are similar. Use this to solve for x:

Similar tri 2

Possible Answers:

Correct answer:

Explanation:

Initially we are given the hypotenuse and one leg of the large triangle, but both legs of the small triangle. To set up a proportion, we need to know both legs of the large triangle, and we can solve for the missing one using the pythagorean theorem:

, where a and b are the legs and c is the hypotenuse.

subtract 64 from both sides

take the square root of both sides

Now that we have both legs, we can see that 15 corresponds with x, and 8 corresponds with 6, so we can set up a proportion to solve for x:

divide both sides by 8

Example Question #3 : Proportions In Similar Triangles

These two triangles are similar. Solve for x:

Similar tri 1

Possible Answers:

Correct answer:

Explanation:

Before we can set up a proportion, we need to know the third side of the larger triangle, since that side is actually the one that corresponds to 6, since both are the shortest sides in their respecitve triangles. We can solve for that side using the Pythagorean Theorem,

 

subtract 100 from both sides

take the square root

Now we can set up a proportion comparing corresponding sides to solve for x:

 cross-multiply

divide by 7.5

 

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