ISEE Middle Level Math : Nets

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

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Example Questions

Example Question #91 : Geometry

Prism

Give the volume of the above box in cubic centimeters.

Possible Answers:

\(\displaystyle 216,000 \textrm{ cm}^{3}\)

\(\displaystyle 324,000 \textrm{ cm}^{3}\)

\(\displaystyle 28,800 \textrm{ cm}^{3}\)

\(\displaystyle 21,600\textrm{ cm}^{3}\)

\(\displaystyle 32,400 \textrm{ cm}^{3}\)

Correct answer:

\(\displaystyle 324,000 \textrm{ cm}^{3}\)

Explanation:

100 centimeters make one meter, so convert each of the dimensions of the box by multiplying by 100.

\(\displaystyle 0.9 \times 100 = 90\) centimeters

\(\displaystyle 0.6 \times 100 = 60\) centimeters

Use the volume formula, substituting \(\displaystyle L = 90, W = H = 60\):

\(\displaystyle V = LWH\)

\(\displaystyle V = 90 \cdot 60 \cdot 60 = 324,000\) cubic centimeters

Example Question #1 : How To Find The Volume Of A Net

A cube made of nickel has sidelength 20 centimeters, Nickel has a density of 8.9 grams per cubic centimeter. What is the mass of this cube?

Possible Answers:

\(\displaystyle 3.56 \textrm{ kg}\)

\(\displaystyle 7.12 \textrm{ kg}\)

\(\displaystyle 35.6 \textrm{ kg}\)

\(\displaystyle 71.2 \textrm{ kg}\)

Correct answer:

\(\displaystyle 71.2 \textrm{ kg}\)

Explanation:

The volume of the cube is \(\displaystyle 20 ^{3} = 20 \times 20 \times 20 = 8,000\) cubic centimeters. Multiply by the number of grams per cubic centimeter to get \(\displaystyle 8,000 \times 8.9 = 71,200\) grams, or \(\displaystyle 71,200 \div 1,000 = 71.2\) kilograms.

Example Question #1 : Volume Of A Rectangular Solid

A rectangular prism has length 24 inches, width 18 inches, and height 15 inches. Give its volume in cubic feet.

Possible Answers:

\(\displaystyle 4 \frac{1}{2} \textrm{ ft}^{3}\)

\(\displaystyle 4 \frac{1}{4} \textrm{ ft}^{3}\)

\(\displaystyle 4 \frac{3}{4} \textrm{ ft}^{3}\)

\(\displaystyle 3 \frac{3}{4} \textrm{ ft}^{3}\)

Correct answer:

\(\displaystyle 3 \frac{3}{4} \textrm{ ft}^{3}\)

Explanation:

Divide each dimension in inches by 12 to convert from inches to feet:

\(\displaystyle L = 24 \div 12 = 2\) feet

\(\displaystyle W = 18 \div 12 = 1 \frac{1}{2} = \frac{3}{2}\) feet

\(\displaystyle H = 15 \div 12 = 1 \frac{1}{4} = \frac{5}{4}\) feet

Multiply the three to get the volume:

\(\displaystyle V = LWH = 2 \cdot \frac{3}{2} \cdot \frac{5}{4} = \frac{15}{4} = 3 \frac{3}{4}\) cubic feet

Example Question #1 : Nets

Prism

Give the volume of the box in cubic inches.

Possible Answers:

\(\displaystyle 3,168 \textrm{ in}^{3}\)

\(\displaystyle 672 \textrm{ in}^{3}\)

\(\displaystyle 1,344 \textrm{ in}^{3}\)

\(\displaystyle 1,056 \textrm{ in}^{3}\)

\(\displaystyle 816 \textrm{ in}^{3}\)

Correct answer:

\(\displaystyle 3,168 \textrm{ in}^{3}\)

Explanation:

Use the volume formula, substituting \(\displaystyle L = 22, W = H = 12\) :

\(\displaystyle V=LWH\)

\(\displaystyle V=22 \cdot 12 \cdot 12 = 3168^{3}\)

Example Question #1 : How To Find The Volume Of A Net

Swimming_pool

One cubic foot is equal to (about) 7.5 gallons.

The above depicts a rectangular swimming pool for an apartment. The pool is seven feet deep everywhere. How many gallons of water does the pool hold?

Possible Answers:

\(\displaystyle 17,850 \textrm{ gal}\)

\(\displaystyle 178,500 \textrm{ gal}\)

\(\displaystyle 89,250 \textrm{ gal}\)

\(\displaystyle 91,875 \textrm{ gal}\)

\(\displaystyle 8,925 \textrm{ gal}\)

Correct answer:

\(\displaystyle 91,875 \textrm{ gal}\)

Explanation:

The pool can be seen as a rectangular prism with dimensions 50 feet by 35 feet by 7 feet; its volume in cubic feet the product of these dimensions, which is 

\(\displaystyle 50 \times 35 \times 7 =12,250\) cubic feet.

One cubic foot is equal to about 7.5 gallons, so multiply:

\(\displaystyle 12,250 \times 7.5 = 91,875\) gallons.

 

Example Question #2 : How To Find The Volume Of A Net

Swimming_pool

The above depicts a rectangular swimming pool for an apartment. The pool is six feet deep everywhere. What is the volume of the pool in cubic feet?

Possible Answers:

\(\displaystyle 51,000\textrm{ ft}^{3}\)

\(\displaystyle 10,500\textrm{ ft}^{3}\)

\(\displaystyle 510\textrm{ ft}^{3}\)

\(\displaystyle 9,500\textrm{ ft}^{3}\)

\(\displaystyle 1,020\textrm{ ft}^{3}\)

Correct answer:

\(\displaystyle 10,500\textrm{ ft}^{3}\)

Explanation:

The pool can be seen as a rectangular prism with dimensions 50 feet by 35 feet by 6 feet; its volume is 

\(\displaystyle 50 \times 35 \times 6 = 10,500\) cubic feet.

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