Common Core: 8th Grade Math : Geometry

Study concepts, example questions & explanations for Common Core: 8th Grade Math

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Example Questions

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 #494 : Grade 8

A sphere has a diameter of  inches. What is the volume of this sphere?

Possible Answers:

 

 

 

 

Correct answer:

 

Explanation:

To find the volume of a sphere, use the following formula:

, where  is the radius of the sphere.

Now, because we are given the diameter of the sphere, divide that value in half to find the radius.

 

Now, plug this value into the volume equation.

  

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

What is the volume of a sphere with a diameter of ?

Possible Answers:

Correct answer:

Explanation:

Write the formula for the volume of the sphere.

The radius is half the diameter, which is five.  Substitute the value.

Example Question #181 : Geometry

A cone has height 18 inches; its base has radius 4 inches. Give its volume in cubic feet (leave in terms of  )

Possible Answers:

Correct answer:

Explanation:

Convert radius and height from inches to feet by dividing by 12:

Height: 18 inches =  feet

Radius: 4 inches = 

The volume of a cone is given by the formula

Substitute :

Example Question #101 : Solid Geometry

A cone has height 240 centimeters; its base has radius 80 centimeters. Give its volume in cubic meters.

Possible Answers:

Correct answer:

Explanation:

Convert both dimensions from centimeters to meters by dividing by 100:

Height: 240 centimeters =   meters.

Radius: 80 centimeters =  meters.

Substitute  in the volume formula:

Example Question #182 : Geometry

Give the volume of a cone whose height is 10 inches and whose base is a circle with circumference  inches. 

Possible Answers:

Correct answer:

Explanation:

A circle with circumference  inches has as its radius 

 inches.

The area of the base is therefore

 square inches.

To find the volume of the cone, substitute  in the formula for the volume of a cone:

 cubic inches

Example Question #183 : Geometry

The height of a cone and the radius of its base are equal. The circumference of the base is  inches. Give its volume.

Possible Answers:

Correct answer:

Explanation:

A circle with circumference  inches has as its radius 

 inches.

The height is also  inches, so substitute  in the volume formula for a cone:

 cubic inches

Example Question #184 : Geometry

In terms of , give the volume, in cubic inches, of a spherical water tank with a diameter of 20 feet.

Possible Answers:

Correct answer:

Explanation:

20 feet =  inches, the diameter of the tank; half of this, or 120 inches, is the radius. Set , substitute in the volume formula, and solve for :

 cubic inches

Example Question #185 : Geometry

A sphere has diameter 3 meters. Give its volume in cubic centimeters (leave in terms of ).

Possible Answers:

Correct answer:

Explanation:

The diameter of 3 meters is equal to  centimeters; the radius is half this, or 150 centimeters. Substitute  in the volume formula:

 cubic centimeters

Example Question #11 : Volume Of A Three Dimensional Figure

A cone has a radius of  inches and a height of  inches. Find the volume of the cone.

Possible Answers:

Correct answer:

Explanation:

The volume of a cone is given by the formula:

Now, plug in the values of the radius and height to find the volume of the given cone.

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