Difference between revisions of "1998 AJHSME Problems/Problem 13"

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==Problem 13==
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==Problem==
  
 
What is the ratio of the area of the shaded square to the area of the large square?  (The figure is drawn to scale)
 
What is the ratio of the area of the shaded square to the area of the large square?  (The figure is drawn to scale)
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<math>\text{(A)}\ \dfrac{1}{6} \qquad \text{(B)}\ \dfrac{1}{7} \qquad \text{(C)}\ \dfrac{1}{8} \qquad \text{(D)}\ \dfrac{1}{12} \qquad \text{(E)}\ \dfrac{1}{16}</math>
 
<math>\text{(A)}\ \dfrac{1}{6} \qquad \text{(B)}\ \dfrac{1}{7} \qquad \text{(C)}\ \dfrac{1}{8} \qquad \text{(D)}\ \dfrac{1}{12} \qquad \text{(E)}\ \dfrac{1}{16}</math>
  
==Solution==
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==Solutions==
  
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=== Solution 1 ===
 
We can divide the large square into quarters by diagonals.
 
We can divide the large square into quarters by diagonals.
  
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<math>\frac{1}{4}\times\frac{1}{2}=\frac{1}{8}=\boxed{C}</math>
 
<math>\frac{1}{4}\times\frac{1}{2}=\frac{1}{8}=\boxed{C}</math>
  
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=== Solution 2 ===
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Answer: '''C'''
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[[File:1998ajhsme-13-2.png]]
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Divide the square into 16 smaller squares as shown. The shaded square is formed from 4 half-squares, so its area is 2. The ratio 2 to 16 is 1/8.
  
 
== See also ==
 
== See also ==
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* [[AJHSME Problems and Solutions]]
 
* [[AJHSME Problems and Solutions]]
 
* [[Mathematics competition resources]]
 
* [[Mathematics competition resources]]
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{{MAA Notice}}

Latest revision as of 00:16, 31 March 2015

Problem

What is the ratio of the area of the shaded square to the area of the large square? (The figure is drawn to scale)

[asy] draw((0,0)--(0,4)--(4,4)--(4,0)--cycle); draw((0,0)--(4,4)); draw((0,4)--(3,1)--(3,3)); draw((1,1)--(2,0)--(4,2)); fill((1,1)--(2,0)--(3,1)--(2,2)--cycle,black); [/asy]

$\text{(A)}\ \dfrac{1}{6} \qquad \text{(B)}\ \dfrac{1}{7} \qquad \text{(C)}\ \dfrac{1}{8} \qquad \text{(D)}\ \dfrac{1}{12} \qquad \text{(E)}\ \dfrac{1}{16}$

Solutions

Solution 1

We can divide the large square into quarters by diagonals.

Then, in $\frac{1}{4}$ the area of the big square, the little square would have $\frac{1}{2}$ the area.

$\frac{1}{4}\times\frac{1}{2}=\frac{1}{8}=\boxed{C}$

Solution 2

Answer: C

1998ajhsme-13-2.png

Divide the square into 16 smaller squares as shown. The shaded square is formed from 4 half-squares, so its area is 2. The ratio 2 to 16 is 1/8.

See also

1998 AJHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 12
Followed by
Problem 14
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
All AJHSME/AMC 8 Problems and Solutions

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