ISEE Upper Level Math : Cylinders

Study concepts, example questions & explanations for ISEE Upper Level Math

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Example Questions

Example Question #423 : Geometry

The axle for a toy car has a length of 4 inches and a diameter of a quarter inch. What is the volume of the axle? Assume it is a cylinder.

Possible Answers:

\(\displaystyle \frac{\pi}{4}in^3\)

\(\displaystyle \frac{\pi}{16}in^3\)

\(\displaystyle 16\pi in^3\)

\(\displaystyle \frac{\pi}{2}in^3\)

Correct answer:

\(\displaystyle \frac{\pi}{16}in^3\)

Explanation:

The axle for a toy car has a length of 4 inches and a diameter of a quarter inch. What is the volume of the axle? Assume it is a cylinder.

Use the following formula for volume of a cylinder

\(\displaystyle V_{cylinder}=\pi r^2h\)

Where r and h are our radius and height, respectively.

In this case, we first need to change our diameter to radius. Because our diameter is one quarter of an inch, our radius will be one eighth of an inch.

Plug it in to get:

\(\displaystyle V_{cylinder}=\pi (\frac{1}{8})^2*4=\pi*\frac{1}{64}in^2*4in=\frac{4\pi}{64}in^3\)

Simplify to get:

\(\displaystyle \frac{4\pi}{64}in^3=\frac{\pi}{16}in^3\)

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

You are visiting the drive-through at the bank. You put you money in a cylindrical tube with a height of 8 inches and a radius of 2 inches. What is the volume of the tube?

Possible Answers:

Not enough information

\(\displaystyle 32\pi in^3\)

\(\displaystyle 16\pi in^3\)

\(\displaystyle 64\pi in^3\)

Correct answer:

\(\displaystyle 32\pi in^3\)

Explanation:

You are visiting the drive-through at the bank. You put you money in a cylindrical tube with a height of 8 inches and a radius of 2 inches. What is the volume of the tube?

Begin with the formula for volume of a cylinder:

\(\displaystyle V_{cylinder}=\pi r^2h\)

We have r and h, which are our radius and height, respectively. Plug them in and solve

\(\displaystyle V_{cylinder}=\pi (2in)^2*8in=\pi*32in^2\)

Making our answer:

\(\displaystyle 32\pi in^2\)

 

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

Find the volume of a cylinder with the following measurements:

  • diameter = 8cm
  • height = 5cm
Possible Answers:

\(\displaystyle 80\pi \text{ cm}^3\)

\(\displaystyle 60\pi \text{ cm}^3\)

\(\displaystyle 20\pi \text{ cm}^3\)

\(\displaystyle 40\pi \text{ cm}^3\)

\(\displaystyle 100\pi \text{ cm}^3\)

Correct answer:

\(\displaystyle 80\pi \text{ cm}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius and h is the height of the cylinder.

 

Now, we know the diameter of the cylinder is 8cm.  We know that the diameter is two times the radius.  Therefore, the radius is 4cm.

We also know the height of the cylinder is 5cm.

Knowing this, we can substitute into the formula.

\(\displaystyle V = \pi \cdot (4\text{cm})^2 \cdot 5\text{cm}\)

\(\displaystyle V = \pi \cdot 16\text{cm}^2 \cdot 5\text{cm}\)

\(\displaystyle V = \pi \cdot 80\text{cm}^3\)

\(\displaystyle V = 80\pi \text{ cm}^3\)

Example Question #4 : How To Find The Volume Of A Cylinder

Find the volume of a cylinder with a diameter of 8in and a height of 7in.

Possible Answers:

\(\displaystyle 68\pi \text{ in}^3\)

\(\displaystyle 112\pi \text{ in}^3\)

\(\displaystyle 56\pi \text{ in}^3\)

\(\displaystyle 121\pi \text{ in}^3\)

\(\displaystyle 78\pi \text{ in}^3\)

Correct answer:

\(\displaystyle 112\pi \text{ in}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius and h is the height of the cylinder.

 

Now, we know the diameter of the cylinder is 8in.  We also know the diameter is two times the radius.  Therefore, the radius is 4in. 

We also know the height of the cylinder is 7in.

Knowing all of this, we can substitute into the formula.  We get

\(\displaystyle V = \pi \cdot(4\text{in})^2 \cdot 7\text{in}\)

\(\displaystyle V = \pi \cdot 16\text{in}^2 \cdot 7\text{in}\)

\(\displaystyle V = \pi \cdot 112\text{in}^3\)

\(\displaystyle V = 112\pi \text{ in}^3\)

Example Question #5 : How To Find The Volume Of A Cylinder

Find the volume of a cylinder with a diameter of 14in and a height of 12in.

Possible Answers:

\(\displaystyle 273\pi \text{ in}^3\)

\(\displaystyle 168\pi \text{ in}^3\)

\(\displaystyle 336\pi \text{ in}^3\)

\(\displaystyle 456\pi \text{ in}^3\)

\(\displaystyle 588\pi \text{ in}^3\)

Correct answer:

\(\displaystyle 588\pi \text{ in}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius, and h is the height of the cylinder.

 

Now, we know the diameter of the cylinder is 14in.  We also know the diameter is two times the radius.  Therefore, the radius is 7in. 

We know the height of the cylinder is 12in.

Knowing all of this, we can substitute into the formula.  We get

\(\displaystyle V = \pi \cdot (7\text{in})^2 \cdot 12\text{in}\)

\(\displaystyle V = \pi \cdot 49\text{in}^2 \cdot 12\text{in}\)

\(\displaystyle V = \pi \cdot 588\text{in}^3\)

\(\displaystyle V = 588\pi \text{ in}^3\)

Example Question #6 : How To Find The Volume Of A Cylinder

Your family owns a farm with a silo for storing grain. If the silo is 40 feet tall and 15 feet in diameter, what volume of grain can it hold?

Possible Answers:

\(\displaystyle 2250 ft^2\)

\(\displaystyle 22.50 \pi ft^3\)

\(\displaystyle 4500 \pi ft^3\)

\(\displaystyle 2250 \pi ft^3\)

Correct answer:

\(\displaystyle 2250 \pi ft^3\)

Explanation:

Your family owns a farm with a silo for storing grain. If the silo is 40 feet tall and 15 feet in diameter, what volume of grain can it hold?

Begin with the formula for volume of a cylinder.

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

A cylinder is just a circle with height. 

So, we know the height is 40 ft, but what is r?

If you said 15, you would be on track to get the problem wrong. That is because the diameter is 15 ft, so our radius is only 7.5 ft.

Plug these in to get our answer:

\(\displaystyle V=\pi (7.5ft)^2(40ft)=2250 \pi ft^3\)

Our answer should be

\(\displaystyle 2250 \pi ft^3\)

Example Question #7 : How To Find The Volume Of A Cylinder

Let \(\displaystyle \pi = 3.14\)

Find the volume of a cylinder with a diameter of 12cm and a height of 7cm.

Possible Answers:

\(\displaystyle 131.88\text{cm}^3\)

\(\displaystyle 263.76\text{cm}^3\)

\(\displaystyle 527.52\text{cm}^3\)

\(\displaystyle 791.28\text{cm}^3\)

\(\displaystyle 923.16\text{cm}^3\)

Correct answer:

\(\displaystyle 791.28\text{cm}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius and h is the height of the cylinder.

 

Now, we know the diameter is 12cm.  We know that the diameter is two times the radius.  Therefore, the radius is 6cm.  

We know the height of the cylinder is 7cm.

We know that \(\displaystyle \pi = 3.14\).

 

Knowing all of this, we can substitute into the formula.  We get

\(\displaystyle V = 3.14 \cdot (6\text{cm})^2 \cdot 7\text{cm}\)

\(\displaystyle V = 3.14 \cdot 36\text{cm}^2 \cdot 7\text{cm}\)

\(\displaystyle V = 3.14 \cdot 252\text{cm}^3\)

\(\displaystyle V = 791.28\text{cm}^3\)

Example Question #1 : Cylinders

You have a tennis ball canister which is cylindrical. If the radius of the cylinder is 3.5 cm, and the height is 21 cm, what is the volume of the canister?

Possible Answers:

\(\displaystyle V=257.25 \pi cm^3\)

\(\displaystyle V=25.725 \pi cm^3\)

\(\displaystyle V=257.25 cm^3\)

\(\displaystyle V=73.5 \pi cm^3\)

Correct answer:

\(\displaystyle V=257.25 \pi cm^3\)

Explanation:

You have a tennis ball canister which is cylindrical. If the radius of the cylinder is 3.5 cm, and the height is 21 cm, what is the volume of the canister?

Begin with the formula for volume of a cylinder:

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

Where r is our radius and h is our height.

Note that the formula is just the formula for the area of a circle times the height, because a cylinder is really just a circle with height.

Now, plug in what we know and solve for V

\(\displaystyle V=\pi (3.5cm)^2 (21cm)=\pi(12.25cm*21cm)=257.25 \pi cm^3\)

So our answer is:

\(\displaystyle V=257.25 \pi cm^3\)

Example Question #9 : How To Find The Volume Of A Cylinder

A cylinder has the following measurements:

Height: 6in
Diameter: 16in

Find the volume.

Possible Answers:

\(\displaystyle 384\pi \text{ in}^3\)

\(\displaystyle 288\pi \text{ in}^3\)

\(\displaystyle 96\pi \text{ in}^3\)

\(\displaystyle 576\pi \text{ in}^3\)

\(\displaystyle 48\pi \text{ in}^3\)

Correct answer:

\(\displaystyle 384\pi \text{ in}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius and h is the height of the cylinder.

 

Now, we know the diameter of the cylinder is 16in.  We also know the diameter is two times the radius.  Therefore, the radius is 8in. 

We also know the height of the cylinder is 6in.

Knowing all of this, we can substitute into the formula.  We get

\(\displaystyle V = \pi \cdot(8\text{in})^2 \cdot 6\text{in}\)

\(\displaystyle V = \pi \cdot 64\text{in}^2 \cdot 6\text{in}\)

\(\displaystyle V = \pi \cdot 384\text{in}^3\)

\(\displaystyle V = 384\pi \text{ in}^3\)

Example Question #10 : How To Find The Volume Of A Cylinder

A cylinder has the following measurements:

Height:  12in
Diameter:  10in

Find the volume.

Possible Answers:

\(\displaystyle 300\pi \text{ in}^3\)

\(\displaystyle 120\pi \text{ in}^3\)

\(\displaystyle 360\pi \text{ in}^3\)

\(\displaystyle 720\pi \text{ in}^3\)

\(\displaystyle 576\pi \text{ in}^3\)

Correct answer:

\(\displaystyle 300\pi \text{ in}^3\)

Explanation:

To find the volume of a cylinder, we will use the following formula:

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

where r is the radius, and h is the height of the cylinder.

 

Now, we know the diameter of the cylinder is 10in.  We also know the diameter is two times the radius.  Therefore, the radius is 5in. 

We know the height of the cylinder is 12in.

Knowing all of this, we can substitute into the formula.  We get

\(\displaystyle V = \pi \cdot (5\text{in})^2 \cdot 12\text{in}\)

\(\displaystyle V = \pi \cdot 25\text{in}^2 \cdot 12\text{in}\)

\(\displaystyle V = \pi \cdot 300\text{in}^3\)

 

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