McGraw Hill Glencoe Geometry, 2012
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McGraw Hill Glencoe Geometry, 2012 View details
4. Volumes of Prisms and Cylinders
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Exercise 38 Page 868

Use some simple solids, like rectangular prisms.

Example Solution:

Practice makes perfect

We are asked to sketch and label in inches three different designs for a measuring cup that holds 1 cup, which is about 14.4375 cubic inches. We could make this cup be a pyramid with some sophisticated base, like below.

However, then there will be a lot of computations to find the exact dimensions of such a cup. Let's make it simple and find measuring cups in the shape of a rectangular prism. We choose this shape because the volume of a rectangular prism is equal to the product of its dimensions, but keep in mind that there are many different solutions to this problem.

Option 1

First, let the measuring cup be in the shape of a cube and s be its side length. Then its volume is V=s^3. We know that the volume of the cup has to be about 14.4375 cubic inches. Let's find s!
V=s^3
14.4375=s^3
Solve for s
sqrt(14.4375)=s
s=sqrt(14.4375)
s≈ 2.43499
s≈ 2.43
Therefore, the side length of the cube should be about 2.43 inches. Now, let's sketch the cube!

Option 2

Now let the measuring cup be in the shape of a square prism with a side base length of 2 inches. Let h denote its height. Then its volume is V=2* 2* h=4h. We know that the volume of the cup has to be about 14.4375 cubic inches. Let's find h!
V=4h
14.4375=4h
Solve for h
3.60938=h
h=3.60938
h≈ 3.61
Therefore, the height of the prism should be about 3.61 inches. Now, let's sketch the prism!

Option 3

Now let the measuring cup be in the shape of a square prism with a side base length of 3 inches. Let h denote its height. Then its volume is V=3* 3* h=9h. We know that the volume of the cup has to be about 14.4375 cubic inches. Let's find h!
V=9h
14.4375=9h
Solve for h
1.60417=h
h=1.60417
h≈ 1.60
Therefore, the height of the prism should be about 1.6 inches. Now, let's sketch the prism!