HiSET: Math : Measurement and Geometry

Study concepts, example questions & explanations for HiSET: Math

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Example Questions

Example Question #1 : Apply Concepts Of Density In Modeling Situations

The graphic below shows a blueprint for a swimming pool.

Swimming pool dimensions

If the pool is going to be 66 inches deep, how many cubic feet of water will it be able to hold? (1 ft = 12 in)

Possible Answers:

Correct answer:

Explanation:

Notice that the outer dimensions of the blueprint are the dimensions for the entire pool, including the concrete, while the inner dimensions are for the part of the pool that will be filled with water. Therefore, we want to focus on just the inner dimensions.

Notice that the depth is given in inches, while the dimensions are in feet. Convert 66 inches to feet by dividing 66 by 12, since 12 inches makes a foot:

The inch units cancel out and leave us with just the feet units. 66 in is 5.5 ft.

Now we have all of the information we need to solve for the volume of the pool. The pool is a rectangular prism, and the formula for volume of a rectangular prism is

(In this case, the "height" of the swimming pool is its depth.)

The blueprint shows that the pool is 40 ft long and 30 ft wide. Plugging in the measurements from the problem, we get

Multiplying this out, we get .

Example Question #2 : Understand Right Triangles

Two of a triangle's interior angles measure  and , respectively. If this triangle's hypotenuse is  long, what are the lengths of its other sides?

Possible Answers:

Correct answer:

Explanation:

A triangle that has interior angles of  and  is necessarily a 30-60-90 triangle—a special right triangle. We can tell that the third angle about which we're not told anything has to be  because a triangle's interior angles always sum to , allowing us to solve for the third angle like so:

Since we know this triangle is a 30-60-90 triangle, we can use the special ratios that always hold true for this triangle's sides and angles to figure out the lengths of its other sides. The following ratio holds true for all 30-60-90 triangles, where the side in a fraction with a given angle is the side opposite that angle.

We're told that the hypotenuse of our triangle has a length of . The hypotenuse is the triangle's longest side, so it will be located directly across from its largest angle. In this case, that angle is . So, we need to set  equivalent to  and solve for .

As you can see, for this particular triangle, . Using this information, we can now calculate the lengths of the other sides of the triangle. The side opposite the  angle will be equal to  inches; since , this side's length is . The side opposite the  angle will be equal to . Substituting in  into this expression, we find that this side has a length of .

Thus, the correct answer is .

Example Question #131 : Measurement And Geometry

30 60 90

Examine the above triangle. Which of the following correctly gives the area of ?

Possible Answers:

None of the other choices gives the correct response.

Correct answer:

Explanation:

Since  is a right angle - that is,  - and , it follows that

,

making  a 30-60-90 triangle. 

By the 30-60-90 Triangle Theorem, 

,

and

Refer to the diagram below:

30 60 90

The area of a right triangle is equal to half the product of the lengths of its legs, so

,

the correct response.

Example Question #1 : Special Triangles

30 60 90

Examine the above triangle. Which of the following correctly gives the perimeter of ?

Possible Answers:

Correct answer:

Explanation:

Since  is a right angle - that is,  - and , it follows that

,

making  a 30-60-90 triangle. 

By the 30-60-90 Triangle Theorem, 

,

and

Refer to the diagram below:

30 60 90

The perimeter - the sum of the sidelengths - is 

.

 

 

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