Difference between revisions of "2012 UNCO Math Contest II Problems/Problem 10"

m (moved 2012 UNC Math Contest II Problems/Problem 10 to 2012 UNCO Math Contest II Problems/Problem 10: disambiguation of University of Northern Colorado with University of North Carolina)
m (See Also)
Line 29: Line 29:
  
 
== See Also ==
 
== See Also ==
{{UNC Math Contest box|n=II|year=2012|num-b=9|num-a=11}}
+
{{UNCO Math Contest box|n=II|year=2012|num-b=9|num-a=11}}
  
 
[[Category:Intermediate Geometry Problems]]
 
[[Category:Intermediate Geometry Problems]]

Revision as of 21:27, 19 October 2014

Problem

An integer equiangular hexagon is a six-sided polygon whose side lengths are all integers and whose internal angles all measure $120^{\circ}$.

(a) How many distinct (i.e., non-congruent) integer equiangular hexagons have no side length greater than $6$? Two such hexagons are shown.

[asy] draw((0,0)--(1,0)--(4,3*sqrt(3))--(3,4*sqrt(3))--(-1,4*sqrt(3))--(-1-3*sqrt(3)/2,4*sqrt(3)-1.5)--cycle,black); MP("1",(.5,0),S);MP("6",(2.5,1.5*sqrt(3)),SE);MP("2",(3.5,3.5*sqrt(3)),NE);MP("4",(1,4*sqrt(3)),N);MP("3",(-1-.75*sqrt(3),4*sqrt(3)-.75),NW);MP("5",(-.5-.75*sqrt(3),2*sqrt(3)-.75),W); draw((8,0)--(11,0)--(13,2*sqrt(3))--(11.5,3.5*sqrt(3))--(7.5,3.5*sqrt(3))--(6,2*sqrt(3))--cycle,black); MP("3",(9.5,0),S);MP("4",(12,sqrt(3)),SE);MP("3",(12.25,2.75*sqrt(3)),NE);MP("4",(9.5,3.5*sqrt(3)),N);MP("3",(6.75,2.75*sqrt(3)),NW);MP("4",(7,sqrt(3)),W); [/asy]


(b) How many distinct integer equiangular hexagons have no side greater than $n$? Give a closed formula in terms of $n$.

(A figure and its mirror image are congruent and are not considered distinct. Translations and rotations of one another are also congruent and not distinct.)


Solution

See Also

2012 UNCO Math Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 9
Followed by
Problem 11
1 2 3 4 5 6 7 8 9 10
All UNCO Math Contest Problems and Solutions