GED Math : 3-Dimensional Geometry

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #31 : Volume Of A Cylinder

What is the radius of a cylinder if it has a height of  and a volume of ?

Possible Answers:

Correct answer:

Explanation:

Recall how to find the volume of a cylinder:

, where  is the radius, and  is the height.

Plug in the given information and solve for the radius.

The radius of the cylinder is .

Example Question #634 : Geometry And Graphs

Determine the volume of a cylinder with a base area of 10, and a height of 20.

Possible Answers:

Correct answer:

Explanation:

Write the formula for the volume of the cylinder.

The base of a cylinder is a circle, and the area of the circle is .

Substitute the base and height into the equation.

The answer is:  

Example Question #81 : 3 Dimensional Geometry

Find the volume of the cylinder with a radius of 7 and a height of 10.

Possible Answers:

Correct answer:

Explanation:

Write the formula for the volume of a cylinder.

Substitute the radius and height into the equation.

The answer is: 

Example Question #82 : 3 Dimensional Geometry

Find the volume of a cylinder with a radius of 3 and a height of 30.

Possible Answers:

Correct answer:

Explanation:

Write the formula for the volume of a cylinder.

Substitute the dimensions.

The answer is:  

Example Question #637 : Geometry And Graphs

Find the volume of the cylinder if the radius is  and the height is .

Possible Answers:

Correct answer:

Explanation:

Write the formula for a cylinder.

Substitute the dimensions.

The answer is:  

Example Question #638 : Geometry And Graphs

Find the volume of the cylinder with a base area of 9, and a height of .

Possible Answers:

Correct answer:

Explanation:

Write the formula for the volume of a cylinder.

The base is a circular shape, and its area is already provided.  This means we can substitute the base area for .

The answer is:  

Example Question #41 : Volume Of A Cylinder

You are filling a cylindrical hole with concrete, and need to know how much concrete to mix. If the hole is  deep and has a radius of 6 inches, what volume of concrete will be needed to fill the hole?

Possible Answers:

Correct answer:

Explanation:

You are filling a cylindrical hole with concrete, and need to know how much concrete to mix. If the hole is  deep and has a radius of , what volume of concrete will be needed to fill the hole?

Our formula for volume of a cylinder is:

Now, before we start plugging stuff in, we need to have all our measurements be in the same units. Let's switch to feet so that we are consistent.

Now, let's plug it in and solve:

So, we need 

 of concrete

Example Question #81 : 3 Dimensional Geometry

In order for Helen to clean her cylindrical fish tank, she must first empty out half the water. If the fish tank has a radius of  inches and a height of  inches, what is the volume of water, in cubic inches, that she will need to empty? Let .

Possible Answers:

Correct answer:

Explanation:

Recall how to find the volume of a cylinder:

Since Helen is only taking out half the water, we will need to find half the volume of the cylindrical fish tank. Thus, we can write the following equation:

Plug in the given radius and height to find the volume of water that Helen needs to remove.

Example Question #81 : 3 Dimensional Geometry

While exploring the woods near your house, you find a cylindrical hole in the ground. You decide that it is dangerous and should be filled in with concrete so that nobody falls in and hurts themselves. You find that the hole is 20 feet deep and 6 feet wide. How many cubic feet of concrete will you need to fill in the hole?

Possible Answers:

Correct answer:

Explanation:

While exploring the woods near your house, you find a cylindrical hole in the ground. You decide that it is dangerous and should be filled in with concrete so that nobody falls in and hurts themselves. You find that the hole is 20 feet deep and 6 feet wide. How many cubic feet of concrete will you need to fill in the hole?

We need to find the volume of a cylinder. Use the following formula

A cylinder is really just a circle with height.

We know our height, 20ft. 

Our radius is half of the width of the hole. In this case, our width is 6ft, so our radius is 3 ft.

Plug these in and find our volume.

So our answer is:

Example Question #41 : Volume Of A Cylinder

How much water would be required to fill a tube which is 3 ft wide and 18 ft long?

Possible Answers:

Correct answer:

Explanation:

How much water would be required to fill a tube which is 3 ft wide and 18 ft long?

We are indirectly asked to find the volume of a cylinder. To do so, we need to following formula:

Where r is the radius of our cylinder, and h is the height.

First, we need to change our diameter (3ft) to our radius. The radius is always half the diameter, so our radius is 1.5 ft

Next, plug in our radius and height and solve for V.

So, we have our answer:

 

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