SAT Math : Geometry

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #711 : Geometry

A cube has a surface area of 24. If we double the height of the cube, what is the volume of the new rectangular box?

Possible Answers:

Correct answer:

Explanation:

We have a cube with a surface area of 24, which means each side has an area of 4. Therefore, the length of each side is 2. If we double the height, the volume becomes .

Example Question #712 : Geometry

A cube has a surface area of 10m2. If a cube's sides all double in length, what is the new surface area?

Possible Answers:

20m2

320m2

40m2

80m2

640m2

Correct answer:

40m2

Explanation:

The equation for surface area of the original cube is 6s2. If the sides all double in length the new equation is 6(2s)2 or 6 * 4s2. This makes the new surface area 4x that of the old. 4x10 = 40m2

Example Question #8 : How To Find The Surface Area Of A Cube

What is the surface area of a cube with a side length of 30?

Possible Answers:

Correct answer:

Explanation:

Write the formula for the surface area of a cube.

Substitute the side.

Example Question #8 : How To Find The Surface Area Of A Cube

The surface areas of six cubes form an arithmetic sequence. The two smallest cubes have sidelengths 10 and 12, respectively. Give the surface area of the largest cube.

Possible Answers:

Correct answer:

Explanation:

The surface area of a cube can be calculated by squaring the sidelength and multiplying by six. The two smallest cubes therefore have surface areas

and

The surface areas form an arithmetic sequence with these two surface areas as the first two terms, so their common difference is 

.

The surface area of the largest, or sixth-smallest, cube, is

Example Question #711 : Geometry

Find the surface area of a cube with side length 2.

Possible Answers:

Correct answer:

Explanation:

To solve, simply use the formula for the surface area of a cube. Thus,

Example Question #21 : Solid Geometry

Find the surface area of a cube given side length of 3.

Possible Answers:

Correct answer:

Explanation:

To find the surface area of a cube means to find the area around the entire object. In the case of a cube, we will need to find that area of all the sides and the top and bottom. Since a cube has equal side lengths, the area of each side and the area of the top and bottom will all be the same.

Recall that the area for a side of a cube is:

From here there are two approaches one can take.

Approach one:

Add all the areas together.

Approach two:

Use the formula for the surface area of a cube,

In this particular case we are given the side length is 3.

Thus we can find the surface area to be,

by approach one,

and by appraoch two,

.

Example Question #11 : How To Find The Surface Area Of A Cube

Find the volume of a cube given side length of 3.

Possible Answers:

Correct answer:

Explanation:

To solve, simply use the formula for the surface area of a cube.

If you do not remember the formula for the test, it is important to draw a picture or to visually conceptualize it. Remember, when finding area of a square or rectangle, you simply multiply the two side lengths. So for a cube in 3 dimensions, you simply have to multiply those three together.

However, a cube is a special case where all three lengths are the same. Thus,

Example Question #22 : Cubes

A cube has given volume . What is its surface area?

Possible Answers:

Correct answer:

Explanation:

First, we need the side length of the cube. Given that , where is a side length, we can solve for  and set  simply by taking the cube root of both sides.

Then we need to remember or realize that the surface area of a cube is because there will be six identical square faces. Plugging in , we get as our answer.

Example Question #713 : Geometry

Find the surface area of a cube with side length 8.

Possible Answers:

Correct answer:

Explanation:

To solve, simply use the formula for the surface area of a cube.

If this is not a formula you have committed to memory, remember that a cube has 6 faces with equal area. So, start by calculating the surface area of one side (64) and add it 6 times. Thus,

Example Question #21 : Cubes

You own a Rubik's cube with a volume of . What is the surface area of the cube?

Possible Answers:

Not enough information to solve

Correct answer:

Explanation:

You own a Rubik's cube with a volume of . What is the surface area of the cube?

To solve for edge length, think of the volume of a cube formula:

Now, we have the volume, so just rearrange it to solve for side length:

Next, recall the surface area of a cube formula:

Plug in and simplify to get:

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