HSPT Math : HSPT Mathematics

Study concepts, example questions & explanations for HSPT Math

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Example Questions

Example Question #1921 : Hspt Mathematics

Square a

The perimeter of the above square is 40% of what number?

Possible Answers:

\(\displaystyle 360\)

\(\displaystyle 57.6\)

\(\displaystyle 120\)

\(\displaystyle 19.2\)

Correct answer:

\(\displaystyle 120\)

Explanation:

The perimeter of a square with sides of length 12 is 4 times this, or

\(\displaystyle 12 \times 4 = 48\).

The number of which 48 is 40% can be found by dividing 48 by 40%, or \(\displaystyle \frac{40}{100}\):

\(\displaystyle 48 \div \frac{40}{100} = 48 \times \frac{100}{40}= 120\)..

Example Question #1922 : Hspt Mathematics

What is the volume of a cube with a side of 9m? 

Possible Answers:

\(\displaystyle 81m^3\)

\(\displaystyle 27m^3\)

\(\displaystyle 729m^3\)

\(\displaystyle 9m^3\)

Correct answer:

\(\displaystyle 729m^3\)

Explanation:

Since volume is length times width times height, and every side on a cube is equal, multiply

\(\displaystyle 9\cdot 9\cdot 9=729\)

The volume of this cube is \(\displaystyle 729\).

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

A cube has six square faces, each with area 64 square inches. Using the conversion factor 1 inch = 2.5 centimeters, give the volume of this cube in cubic centimeters, rounding to the nearest whole number.

Possible Answers:

800 cubic centimeters

2,000 cubic centimeters

4,000 cubic centimeters

400 cubic centimeters

8,000 cubic centimeters

Correct answer:

8,000 cubic centimeters

Explanation:

The volume of a cube is the cube of its sidelength, which is also the sidelength of each square face. This sidelength is the square root of the area 64:

\(\displaystyle \sqrt{64}=8\) inches.

Multiply this by 2.5 to get the sidelength in centimeters:

\(\displaystyle 8\) \(\displaystyle \times 2.5\) \(\displaystyle = 20\) centimeters.

The cube of this is 

\(\displaystyle 20^{3}\)  \(\displaystyle =8000\) cubic centimeters

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

A cube has a side length of 5 inches. Give the volume and surface area of the cube.

Possible Answers:

\(\displaystyle 125 in^3 ,75 in^2\)

\(\displaystyle 25 in^3 ,75 in^2\)

\(\displaystyle 250in^3, 150 in^2\)

\(\displaystyle 125 in^3 ,150 in^2\)

\(\displaystyle 25 in^3 ,150 in^2\)

Correct answer:

\(\displaystyle 125 in^3 ,150 in^2\)

Explanation:

A cube has all edges the same length. The volume of a cube is found by multiplying the length of any edge by itself twice. As a formula:

 

\(\displaystyle Volume=s^3\) where \(\displaystyle s\) is the length of any edge of the cube.

The Surface Area of a cube can be calculated as \(\displaystyle 6s^2\).

 

So we get:

 

Volume \(\displaystyle =s^3=5^3=125 in^3\)

Surface area\(\displaystyle =6s^2=6\times 5^2=6\times 25=150 in^2\)

Example Question #2 : Know And Use The Formulas For The Volumes Of Cones, Cylinders, And Spheres: Ccss.Math.Content.8.G.C.9

The height of a cylinder is 3 inches and the radius of the circular end of the cylinder is 3 inches. Give the volume and surface area of the cylinder.

Possible Answers:

\(\displaystyle V=74.78 in^3, A=113.10in^2\)

\(\displaystyle V=74.78 in^3, A=103.04in^2\)

\(\displaystyle V=84.78 in^3, A=123.04in^2\)

\(\displaystyle V=84.82 in^3, A=113.10in^2\)

\(\displaystyle V=84.78 in^3, A=103.04in^2\)

Correct answer:

\(\displaystyle V=84.82 in^3, A=113.10in^2\)

Explanation:

The volume of a cylinder is found by multiplying the area of one end of the cylinder (base) by its height or:

 \(\displaystyle Volume=\pi r^2h\)

where \(\displaystyle r\) is the radius of the circular end of the cylinder and \(\displaystyle h\) is the height of the cylinder. So we can write:

 

\(\displaystyle Volume=\pi r^2h=\pi \times 3^2\times 3=84.82in^3\)

 

The surface area of the cylinder is given by:

 

\(\displaystyle A=2\pi r^2+2\pi rh\)

 

where \(\displaystyle A\) is the surface area of the cylinder, \(\displaystyle r\) is the radius of the cylinder and \(\displaystyle h\) is the height of the cylinder. So we can write:

\(\displaystyle A=2\pi r^2+2\pi rh\)

\(\displaystyle A=2\pi (3)^2+2\pi \times 3\times 3\)

\(\displaystyle A=18\pi+18\pi\)

\(\displaystyle A=36\pi\)

\(\displaystyle A=113.10\)

Example Question #3 : Know And Use The Formulas For The Volumes Of Cones, Cylinders, And Spheres: Ccss.Math.Content.8.G.C.9

The end (base) of a cylinder has an area of \(\displaystyle 16\pi\) square inches. If the height of the cylinder is half of the radius of the base of the cylinder, give the volume of the cylinder.

Possible Answers:

\(\displaystyle 8\pi\)

\(\displaystyle 32\pi\)

\(\displaystyle 16\)

\(\displaystyle 16\pi\)

\(\displaystyle 32\)

Correct answer:

\(\displaystyle 32\pi\)

Explanation:

The area of the end (base) of a cylinder is \(\displaystyle \pi r^2\), so we can write:

\(\displaystyle \pi r^2=16\pi\Rightarrow r^2=16\Rightarrow r=4\ inches\)

 

The height of the cylinder is half of the radius of the base of the cylinder, that means:

 

\(\displaystyle h=\frac{r}{2}=\frac{4}{2}=2\ inches\)

 

The volume of a cylinder is found by multiplying the area of one end of the cylinder (base) by its height:

\(\displaystyle Volume=Area\times h=16\pi\times 2=32\pi\)

or

\(\displaystyle Volume=\pi r^2h=\pi\times 4^2\times 2=32\pi\)

Example Question #4 : Know And Use The Formulas For The Volumes Of Cones, Cylinders, And Spheres: Ccss.Math.Content.8.G.C.9

We have two right cylinders. The radius of the base Cylinder 1 is \(\displaystyle \sqrt{3}\) times more than that of Cylinder 2, and the height of Cylinder 2 is 4 times more than the height of Cylinder 1. The volume of Cylinder 1 is what fraction of the volume of Cylinder 2?

Possible Answers:

\(\displaystyle V_{1}=V_{2}\)

\(\displaystyle V_{1}=\frac{4}{3}V_{2}\)

\(\displaystyle V_{1}=\frac{2}{3}V_{2}\)

\(\displaystyle V_{1}=\frac{3}{4}V_{2}\)

\(\displaystyle V_{1}=\frac{3}{2}V_{2}\)

Correct answer:

\(\displaystyle V_{1}=\frac{3}{4}V_{2}\)

Explanation:

The volume of a cylinder is:

\(\displaystyle V=\pi r^2h\)

where \(\displaystyle V\) is the volume of the cylinder, \(\displaystyle r\)  is the radius of the circular end of the cylinder, and \(\displaystyle h\) is the height of the cylinder.

 

So we can write:

 

\(\displaystyle V_{1}=\pi (r_{1})^2h_{1}\)

and

\(\displaystyle V_{2}=\pi (r_{2})^2h_{2}\)

 

Now we can summarize the given information:

\(\displaystyle r_{1}=\sqrt{3}\cdot r_{2}\)

\(\displaystyle h_{2}=4\cdot h_{1}\Rightarrow h_{1}=\frac{h_{2}}{4}\)

 

Now substitute them in the \(\displaystyle V_{1}\) formula:

 

\(\displaystyle V_{1}=\pi (\sqrt{3}r_{2})^2\times \frac{h_{2}}{4}\Rightarrow V_{1}=\frac{3}{4}\pi (r_{2})^2\times h_{2}\Rightarrow V_{1}=\frac{3}{4}V_{2}\)

Example Question #2 : Know And Use The Formulas For The Volumes Of Cones, Cylinders, And Spheres: Ccss.Math.Content.8.G.C.9

Two right cylinders have the same height. The radius of the base of the first cylinder is two times more than that of the second cylinder. Compare the volume of the two cylinders.

Possible Answers:

\(\displaystyle V_{1}=3\cdot V_{2}\)

\(\displaystyle V_{1}=4\cdot V_{2}\)

\(\displaystyle V_{1}=V_{2}\)

\(\displaystyle V_{1}=\sqrt{2}\cdot V_{2}\)

\(\displaystyle V_{1}=2\cdot V_{2}\)

Correct answer:

\(\displaystyle V_{1}=4\cdot V_{2}\)

Explanation:

The volume of a cylinder is:

\(\displaystyle V=\pi r^2h\)

where \(\displaystyle r\) is the radius of the circular end of the cylinder and \(\displaystyle h\) is the height of the cylinder. So we can write:

\(\displaystyle V_{1}=\pi (r_{1})^2h_{1}\)

\(\displaystyle V_{2}=\pi (r_{2})^2h_{2}\)

 

We know that 

\(\displaystyle h_{1}=h_{2}\)

and 

\(\displaystyle r_{1}=2r_{2}\).

 

So we can write:

\(\displaystyle V_{1}=\pi (r_{1})^2h_{1}=\pi (2r_{2})^2\cdot h_{2}=4\pi (r_{2})^2h_{2}\Rightarrow V_{1}=4V_{2}\)

Example Question #1 : Volume Of A Three Dimensional Figure

A car dealership wants to fill a large spherical advertising ballon with helium. It can afford to buy 1,000 cubic yards of helium to fill this balloon. What is the greatest possible diameter of that balloon (nearest tenth of a yard)?

Possible Answers:

\(\displaystyle 9.3 \;\textrm{yd}\)

\(\displaystyle 7.7 \;\textrm{yd}\)

\(\displaystyle 15.4 \;\textrm{yd}\)

\(\displaystyle 12.4 \;\textrm{yd}\)

\(\displaystyle 6.2 \;\textrm{yd}\)

Correct answer:

\(\displaystyle 12.4 \;\textrm{yd}\)

Explanation:

The volume of a sphere, given its radius, is 

\(\displaystyle V = \frac{4\pi r^{3}}{3}\)

Set \(\displaystyle V = 1,000\), solve for \(\displaystyle r\), and double that to get the diameter.

\(\displaystyle 1,000= \frac{4\pi r^{3}}{3}\)

\(\displaystyle r^{3} = \frac{1,000 \cdot 3 }{4\pi} \approx 238.7\)

\(\displaystyle r \approx \sqrt[3]{238.7} \approx 6.2\)

The diameter is twice this, or 12.4 yards.

Example Question #2 : Volume Of A Three Dimensional Figure

The diameter of a sphere is \(\displaystyle 6t\). Give the volume of the sphere in terms of \(\displaystyle t\).

Possible Answers:

\(\displaystyle 36\pi t^3\)

\(\displaystyle 72\pi t^3\)

\(\displaystyle 10\pi t^3\)

\(\displaystyle 30\pi t^3\)

\(\displaystyle 24\pi t^3\)

Correct answer:

\(\displaystyle 36\pi t^3\)

Explanation:

The diameter of a sphere is \(\displaystyle 6t\) so the radius of the sphere would be \(\displaystyle 6t\div 2=3t\)

 

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

\(\displaystyle Volume=\frac{4}{3}\pi r^3=\frac{4}{3}\pi \times (3t)^3=\frac{4}{3}\pi\times 27t^3\Rightarrow Volume=36\pi t^3\) 

 

 

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