Difference between revisions of "2007 iTest Problems/Problem 27"

(Created page with "== Problem == The face diagonal of a cube has length <math>4</math>. Find the value of n given that <math>n\sqrt2</math> is the <math>\textit{volume}</math> of the cube. == Sol...")
 
(Solution to Problem 27)
 
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The face diagonal of a cube has length <math>4</math>. Find the value of n given that <math>n\sqrt2</math> is the <math>\textit{volume}</math> of the cube.
 
The face diagonal of a cube has length <math>4</math>. Find the value of n given that <math>n\sqrt2</math> is the <math>\textit{volume}</math> of the cube.
  
== Solution ==
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==Solution==
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<asy>
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draw((0,0)--(10,0)--(10,10)--(0,10)--(0,0));
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draw((10,0)--(0,10));
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label("$4$",(5,5),NE);
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label("$s$",(5,0),S);
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label("$s$",(0,5),W);
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</asy>
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If the length of the face diagonal of the cube is <math>4</math>, then by using 45-45-90 triangles, the side length of the cube is <math>2 \sqrt{2}</math>.  Thus, the volume of the cube is <math>(2 \sqrt{2})^3 = 16 \sqrt{2}</math>, so <math>n = \boxed{16}</math>.
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==See Also==
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{{iTest box|year=2007|num-b=26|num-a=28}}
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[[Category:Introductory Geometry Problems]]

Latest revision as of 19:15, 10 June 2018

Problem

The face diagonal of a cube has length $4$. Find the value of n given that $n\sqrt2$ is the $\textit{volume}$ of the cube.

Solution

[asy]  draw((0,0)--(10,0)--(10,10)--(0,10)--(0,0)); draw((10,0)--(0,10)); label("$4$",(5,5),NE); label("$s$",(5,0),S); label("$s$",(0,5),W);  [/asy]

If the length of the face diagonal of the cube is $4$, then by using 45-45-90 triangles, the side length of the cube is $2 \sqrt{2}$. Thus, the volume of the cube is $(2 \sqrt{2})^3 = 16 \sqrt{2}$, so $n = \boxed{16}$.

See Also

2007 iTest (Problems, Answer Key)
Preceded by:
Problem 26
Followed by:
Problem 28
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 TB1 TB2 TB3 TB4