Difference between revisions of "2001 AMC 10 Problems/Problem 5"

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we find <math> \boxed{\textbf{(D)}\ 6} </math> pentominoes.
 
we find <math> \boxed{\textbf{(D)}\ 6} </math> pentominoes.
  
== Solution ==
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== See Also ==
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{{AMC10 box|year=2001|num-b=4|num-a=6}}

Revision as of 12:35, 16 March 2011

Problem

How many of the twelve pentominoes pictured below at least one line of symmetry?

$\textbf{(A)}\ 3 \qquad \textbf{(B)}\ 4 \qquad \textbf{(C)}\ 5 \qquad \textbf{(D)}\ 6 \qquad \textbf{(E)}\ 7$

Solution

Here is the picture: http://www.artofproblemsolving.com/Forum/download/file.php?id=6659&&mode=view

The ones with lines over the shapes have at least one line of symmetry. Counting the number of shapes that have line(s) on them, we find $\boxed{\textbf{(D)}\ 6}$ pentominoes.

See Also

2001 AMC 10 (ProblemsAnswer KeyResources)
Preceded by
Problem 4
Followed by
Problem 6
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 AMC 10 Problems and Solutions