ISEE Upper Level Math : Geometry

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

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Example Questions

Example Question #361 : Geometry

While exploring an ancient ruin, you discover a small puzzle cube. You measure the side length to be \(\displaystyle 12 cm\). Find the cube's surface area.

Possible Answers:

\(\displaystyle 864cm^2\)

\(\displaystyle 144cm^3\)

\(\displaystyle 1728 cm^2\)

\(\displaystyle 866cm^3\)

Correct answer:

\(\displaystyle 864cm^2\)

Explanation:

While exploring an ancient ruin, you discover a small puzzle cube. You measure the side length to be \(\displaystyle 12 cm\). Find the cube's surface area.

To find the surface area, use the following formula:

\(\displaystyle SA=6s^2=6(12cm)^2=864cm^2\)

Example Question #362 : Geometry

Find the surface area of a cube with a base of 8in.

Possible Answers:

\(\displaystyle 384\text{in}^2\)

\(\displaystyle 212\text{in}^2\)

\(\displaystyle 336\text{in}^2\)

\(\displaystyle 128\text{in}^2\)

\(\displaystyle 48\text{in}^2\)

Correct answer:

\(\displaystyle 384\text{in}^2\)

Explanation:

A cube has all equal sides (length, width, height).  To find the surface area of a cube, we will use the following formula:

\(\displaystyle SA = 6a^2\)

 

Now, we know the base of the cube is 8in.  Because all sides are equal (i.e. all sides are 8in), we will use that to substitute into the formula.  We get

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

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

\(\displaystyle SA = 384\text{in}^2\)

Example Question #33 : Cubes

You are building a box to hold your collection of rare rocks. You want to build a cube-shaped box with a side length of 3 feet. If you do so, what will the surface area of your box be?

Possible Answers:

\(\displaystyle 18ft^2\)

\(\displaystyle 54 ft^2\)

\(\displaystyle 60 ft^2\)

\(\displaystyle 27ft^2\)

Correct answer:

\(\displaystyle 54 ft^2\)

Explanation:

You are building a box to hold your collection of rare rocks. You want to build a cube-shaped box with a side length of 3 feet. If you do so, what will the surface area of your box be?

To find the surface area, use the formula:

\(\displaystyle SA=6s^2\)

Where s is our side length and SA is our surface area.

Plug in our known and simplify

\(\displaystyle SA=6 (3ft)^2=6*9ft^2=54ft^2\)

So, our answer is 

\(\displaystyle 54ft^2\)

Example Question #34 : Cubes

Find the surface area of a cube with a length of 11in.

Possible Answers:

\(\displaystyle 649\text{in}^2\)

\(\displaystyle 512\text{in}^2\)

\(\displaystyle 121\text{in}^2\)

\(\displaystyle 726\text{in}^2\)

\(\displaystyle 44\text{in}^2\)

Correct answer:

\(\displaystyle 726\text{in}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula:

\(\displaystyle SA = 6a^2\)

where a is the length of any side of the cube.  Because it is a cube, all sides are equal.  Therefore, we can use any side in the formula.

Now, we know the length of the cube is 11in.  We can substitute that into the formula.  We get

\(\displaystyle SA = 6 \cdot (11\text{in})^2\)

\(\displaystyle SA = 6 \cdot 121\text{in}^2\)

\(\displaystyle SA = 726\text{in}^2\)

Example Question #35 : Cubes

Find the surface area of a cube with a width of 7cm.

Possible Answers:

\(\displaystyle 294\text{cm}^2\)

\(\displaystyle 442\text{cm}^2\)

\(\displaystyle 343\text{cm}^2\)

\(\displaystyle \text{There is not enough information to solve the problem.}\)

\(\displaystyle 368\text{cm}^2\)

Correct answer:

\(\displaystyle 294\text{cm}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula.

\(\displaystyle SA = 6a^2\)

where a is the length of any side of the cube.  We can use any side because all sides have the same length on a cube.

Now, we know the width of the cube is 7cm.  So, we can substitute.  We get

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

\(\displaystyle SA = 6 \cdot 49\text{cm}^2\)

\(\displaystyle SA = 294\text{cm}^2\)

Example Question #36 : Cubes

Find the surface area of a cube with a width of 7in.

Possible Answers:

\(\displaystyle 343\text{in}^2\)

\(\displaystyle 147\text{in}^2\)

\(\displaystyle 294\text{in}^2\)

\(\displaystyle 245\text{in}^2\)

\(\displaystyle 84\text{in}^2\)

Correct answer:

\(\displaystyle 294\text{in}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula.

\(\displaystyle SA = 6a^2\)

where a is the length of any side of the cube.

 

Now, we know the width of the cube is 7in.  Because it is a cube, all sides are equal (this is why we can use any length in the formula).  So, we will use 7in in the formula.  We get

\(\displaystyle SA = 6 \cdot (7\text{in})^2\)

\(\displaystyle SA = 6 \cdot 49\text{in}^2\)

\(\displaystyle SA = 294\text{in}^2\)

Example Question #37 : Cubes

Find the surface area of a cube with a width of 6in.

Possible Answers:

\(\displaystyle 27\text{in}^2\)

\(\displaystyle 216\text{in}^2\)

\(\displaystyle 72\text{in}^2\)

\(\displaystyle 144\text{in}^2\)

\(\displaystyle 432\text{in}^2\)

Correct answer:

\(\displaystyle 216\text{in}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula:

\(\displaystyle SA = 6 \cdot l \cdot w\)

where l is the length, and w is the width of the cube.

 

Now, we know the width of the cube is 6in.  Because it is a cube, all lengths, widths, and heights are the same.  Therefore, the length is also 6in.

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

\(\displaystyle SA = 6 \cdot 6\text{in} \cdot 6\text{in}\)

\(\displaystyle SA = 6 \cdot 36\text{in}^2\)

\(\displaystyle SA = 216\text{in}^2\)

Example Question #38 : Cubes

Find the surface area of a cube with a length of 9cm.

Possible Answers:

\(\displaystyle 324\text{cm}^2\)

\(\displaystyle 218\text{cm}^2\)

\(\displaystyle 486\text{cm}^2\)

\(\displaystyle 338\text{cm}^2\)

\(\displaystyle 576\text{cm}^2\)

Correct answer:

\(\displaystyle 486\text{cm}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula: 

\(\displaystyle SA = 6 a^2\)

where a is the length of one side of the cube. 

Now, we know the length of the cube is 9cm. So, we get

\(\displaystyle SA = 6 \cdot (9\text{cm})^2\)

\(\displaystyle SA = 6 \cdot 81\text{cm}^2\)

\(\displaystyle SA = 486\text{cm}^2\)

Example Question #39 : Cubes

Find the surface area of a cube with a width of 6cm.

Possible Answers:

\(\displaystyle 361\text{cm}^2\)

\(\displaystyle 216\text{cm}^2\)

\(\displaystyle 96\text{cm}^2\)

\(\displaystyle 128\text{cm}^2\)

\(\displaystyle 428\text{cm}^2\)

Correct answer:

\(\displaystyle 216\text{cm}^2\)

Explanation:

To find the surface area of a cube, we will use the following formula.

\(\displaystyle SA = 6a^2\)

where a is the length of any side of the cube.

Now, we know the width of the cube is 6cm.

So, we get

\(\displaystyle SA = 6 \cdot (6\text{cm})^2\)

\(\displaystyle SA = 6 \cdot 6\text{cm}^2\)

\(\displaystyle SA = 216\text{cm}^2\)

Example Question #1 : How To Find The Length Of An Edge Of A Cube

The volume of a cube is \(\displaystyle 64\). What is the length of an edge of the cube?

Possible Answers:

\(\displaystyle 32\)

\(\displaystyle 4\)

\(\displaystyle 16\)

\(\displaystyle 8\)

Correct answer:

\(\displaystyle 4\)

Explanation:

Let \(\displaystyle x\) be the length of an edge of the cube. The volume of a cube can be determined by the equation:
\(\displaystyle x^3=V\)

\(\displaystyle x^3=64\)

\(\displaystyle \sqrt[3]{x^3}=\sqrt[3]{64}\)

\(\displaystyle x=4\)

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