All GRE Math Resources
Example Questions
Example Question #1 : How To Find The Surface Area Of A Cylinder
What is the surface area of a cylinder that has a diameter of 6 inches and is 4 inches tall?
The formula for the surface area of a cylinder is ,
where is the radius and is the height.
Example Question #1 : Cylinders
A cylinder has a radius of 4 and a height of 8. What is its surface area?
This problem is simple if we remember the surface area formula!
Example Question #3 : How To Find The Surface Area Of A Cylinder
Quantitative Comparison
Quantity A: Surface area of a cylinder that is 2 feet high and has a radius of 4 feet
Quantity B: Surface area of a box that is 3 feet wide, 2 feet high, and 4 feet long
Quantity A is greater.
The two quantities are equal.
The relationship cannot be determined from the information given.
Quantity B is greater.
Quantity A is greater.
Quantity A: SA of a cylinder = 2πr2 + 2πrh = 2π * 16 + 2π * 4 * 2 = 48π
Quantity B: SA of a rectangular solid = 2ab + 2bc + 2ac = 2 * 3 * 2 + 2 * 2 * 4 + 2 * 3 * 4 = 52
48π is much larger than 52, because π is approximately 3.14.
Example Question #1 : Cylinders
A cylinder has a height of 4 and a circumference of 16π. What is its volume
256π
16π
none of these
128π
64π
256π
circumference = πd
d = 2r
volume of cylinder = πr2h
r = 8, h = 4
volume = 256π
Example Question #1 : How To Find The Volume Of A Cylinder
Rusty is considering making a cylindrical grain silo to store his crops. He has an area that is 6 feet long, 6 feet wide and 12 feet tall to build a cylinder in. What is the maximum volume of grain that he can store in this cylinder?
The maximum cylindrical base can have a diameter of 6 and therefore a radius of 3. The formula for the volume of a cylinder is , which in this case is .
Example Question #2 : How To Find The Volume Of A Cylinder
A cylinder with volume of and a radius of has its radius doubled. What is the volume of the new cylinder?
To begin, you must solve for the height of the original cylinder. We know:
For our values, we know:
Now, divide both sides by :
So, if we have a new radius of , our volume will be:
Example Question #11 : Solid Geometry
If the dimensions of a rectangular crate are , which of the following CANNOT be the total surface area of two sides of the crate?
Side 1: surface area of the 6 x 7 side is 42
Side 2: surface area of the 7 x 8 side is 56
Side 3: surface area of the 6 x 8 side is 48.
We can add sides 1 and 3 to get 90, so that's not the answer.
We can add sides 1 and 1 to get 84, so that's not the answer.
We can add sides 2 and 3 to get 104, so that's not the answer.
We can add sides 2 and 2 to get 112, so that's not the answer.
This leaves the answer of 92. Any combination of the three sides of the rectangular prism will not give us 92 as the total surface area.
Example Question #314 : Geometry
Kate wants to paint a cylinder prism.
What is the surface area of her prism if it is inches tall and has a diameter of inches? Round to the nearest whole number.
First, find the area of the base of the cyclinder:
and multiply that by two, since there are two sides with this measurement: .
Then, you find the width of the rectangular portion (label portion) of the prism by finding the circumference of the cylinder:
. This is then multiplied by the height of the cylinder to find the area of the rectanuglar portion of the cylinder: .
Finally, add all sides together and round: .
Example Question #2 : How To Find The Surface Area Of A Prism
This triangular prism has a height of feet and a length of feet.
What is the surface area of the prism? Round to the nearest tenth.
Find the area of the triangular sides first:
Since there are two sides of this area, we multiply the area by 2:
Next find the area of the rectangular regions. Two of them have the width of 3 feet and a length of 7 feet, while the last one has a width measurement of feet and a length of 7 feet. Multiply and add all other sides:
.
Lastly, add the triangular sides to the rectangular sides and round:
.
Example Question #1 : How To Find The Volume Of A Prism
A rectangular prism has a width of 3 units, a length that is twice the width, and a height that is two-thirds the length. What is the volume of the prism?
Remember, the formula for the volume of a rectangular prism is width times height times length:
Now, let's solve the word problem for each of these values. We know that . If length is double the width, then the length must be 6 units. If the height is two-thirds the length, then the height must be 4:
Multiply all three values together to solve for the volume:
The volume of the rectangular prism is units cubed.