HSPT Math : HSPT Mathematics

Study concepts, example questions & explanations for HSPT Math

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Example Questions

Example Question #493 : Grade 8

A spherical balloon has a diameter of 10 meters. Give the volume of the balloon.

Possible Answers:

Correct answer:

Explanation:

The volume enclosed by a sphere is given by the formula:

where  is the radius of the sphere. The diameter of the balloon is 10 meters so the radius of the sphere would be meters. Now we can get:

 

Example Question #3 : Volume Of A Three Dimensional Figure

The volume of a sphere is 1000 cubic inches. What is the diameter of the sphere.

Possible Answers:

Correct answer:

Explanation:

The volume of a sphere is:

 

Where is the radius of the sphere. We know the volume and can solve the formula for :

 

 inches

 

So we can get:

 

Example Question #1335 : Concepts

Prism

Give the volume of the above box in cubic centimeters.

Possible Answers:

Correct answer:

Explanation:

100 centimeters make one meter, so convert each of the dimensions of the box by multiplying by 100.

 centimeters

 centimeters

Use the volume formula, substituting :

 cubic centimeters

Example Question #1 : Solid Geometry

A cube made of nickel has sidelength 20 centimeters, Nickel has a density of 8.9 grams per cubic centimeter. What is the mass of this cube?

Possible Answers:

Correct answer:

Explanation:

The volume of the cube is  cubic centimeters. Multiply by the number of grams per cubic centimeter to get  grams, or  kilograms.

Example Question #1 : Volume Of A Rectangular Solid

A rectangular prism has length 24 inches, width 18 inches, and height 15 inches. Give its volume in cubic feet.

Possible Answers:

Correct answer:

Explanation:

Divide each dimension in inches by 12 to convert from inches to feet:

 feet

 feet

 feet

Multiply the three to get the volume:

 cubic feet

Example Question #1341 : Concepts

Prism

Give the volume of the box in cubic inches.

Possible Answers:

Correct answer:

Explanation:

Use the volume formula, substituting  :

Example Question #1 : How To Find The Volume Of A Sphere

A cube with sides of 4” each contains a floating sphere with a radius of 1”.  What is the volume of the space outside of the sphere, within the cube?

Possible Answers:

59.813 in3

11.813 in3

4.187 in3

11.813 in3

64 in3

Correct answer:

59.813 in3

Explanation:

Volume of Cube = side3 = (4”)3 = 64 in3

Volume of Sphere = (4/3) * π * r3 = (4/3) * π * 13 = (4/3) * π * 13 = (4/3) * π = 4.187 in3

Difference = Volume of Cube – Volume of Sphere = 64 – 4.187 = 59.813 in3

Example Question #2 : How To Find The Volume Of A Sphere

If a sphere's diameter is doubled, by what factor is its volume increased?

Possible Answers:

16

4

3

2

8

Correct answer:

8

Explanation:

The formula for the volume of a sphere is 4πr3/3. Because this formula is in terms of the radius, it would be easier for us to determine how the change in the radius affects the volume. Since we are told the diameter is doubled, we need to first determine how the change in the diameter affects the change in radius.

Let us call the sphere's original diameter d and its original radius r. We know that d = 2r.

Let's call the final diameter of the sphere D. Because the diameter is doubled, we know that D = 2d. We can substitute the value of d and obtain D = 2(2r) = 4r.

Let's call the final radius of the sphere R. We know that D = 2R, so we can now substituate this into the previous equation and write 2R = 4r. If we simplify this, we see that R = 2r. This means that the final radius is twice as large as the initial radius.

The initial volume of the sphere is 4πr3/3. The final volume of the sphere is 4πR3/3. Because R = 2r, we can substitute the value of R to obtain 4π(2r)3/3. When we simplify this, we get 4π(8r3)/3 = 32πr3/3.

In order to determine the factor by which the volume has increased, we need to find the ratio of the final volume to the initial volume.

32πr3/3 divided by 4πr3/3 = 8

The volume has increased by a factor of 8. 

Example Question #3 : How To Find The Volume Of A Sphere

A sphere increases in volume by a factor of 8. By what factor does the radius change?

Possible Answers:

4

10

8

6

2

Correct answer:

2

Explanation:

Volume of a sphere is 4Πr3/3. Setting that equation equal to the original volume, the new volume is given as 8*4Πr3/3, which can be rewritten as 4Π8r3/3, and can be added to the radius value by 4Π(2r)3/3 since 8 si the cube of 2. This means the radius goes up by a factor of 2

Example Question #1 : How To Find The Volume Of A Sphere

A foam ball has a volume of 2 units and has a diameter of x. If a second foam ball has a radius of 2x, what is its volume?

Possible Answers:

128 units

4 units

16 units

8 units

2 units

Correct answer:

128 units

Explanation:

Careful not to mix up radius and diameter. First, we need to identify that the second ball has a radius that is 4 times as large as the first ball.  The radius of the first ball is (1/2)x and the radius of the second ball is 2x. The volume of the second ball will be 43, or 64 times bigger than the first ball.  So the second ball has a volume of 2 * 64 = 128.

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