Difference between revisions of "1998 AHSME Problems/Problem 15"

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== Problem 15 ==
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== Problem==
 
A regular hexagon and an equilateral triangle have equal areas. What is the ratio of the length of a side of the triangle to the length of a side of the hexagon?
 
A regular hexagon and an equilateral triangle have equal areas. What is the ratio of the length of a side of the triangle to the length of a side of the hexagon?
  
 
<math> \mathrm{(A) \ }\sqrt{3} \qquad \mathrm{(B) \ }2 \qquad \mathrm{(C) \ }\sqrt{6} \qquad \mathrm{(D) \ }3 \qquad \mathrm{(E) \ }6 </math>
 
<math> \mathrm{(A) \ }\sqrt{3} \qquad \mathrm{(B) \ }2 \qquad \mathrm{(C) \ }\sqrt{6} \qquad \mathrm{(D) \ }3 \qquad \mathrm{(E) \ }6 </math>
  
[[1998 AHSME Problems/Problem 15|Solution]]
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==Solution==
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<math>A_{\triangle} = \frac{s_t^2\sqrt{3}}{4}</math>
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<math>A_{hex} = \frac{6s_h^2\sqrt{3}}{4}</math> since a regular hexagon is just six equilateral triangles.
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Setting the areas equal, we get:
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<math>s_t^2 = 6s_h^2</math>
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<math>\left(\frac{s_t}{s_h}\right)^2 = 6</math>
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<math>\frac{s_t}{s_h} = \sqrt{6}</math>, and the answer is <math>\boxed{C}</math>.
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== See also ==
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{{AHSME box|year=1998|num-b=14|num-a=16}}
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{{MAA Notice}}

Latest revision as of 14:29, 5 July 2013

Problem

A regular hexagon and an equilateral triangle have equal areas. What is the ratio of the length of a side of the triangle to the length of a side of the hexagon?

$\mathrm{(A) \ }\sqrt{3} \qquad \mathrm{(B) \ }2 \qquad \mathrm{(C) \ }\sqrt{6} \qquad \mathrm{(D) \ }3 \qquad \mathrm{(E) \ }6$

Solution

$A_{\triangle} = \frac{s_t^2\sqrt{3}}{4}$

$A_{hex} = \frac{6s_h^2\sqrt{3}}{4}$ since a regular hexagon is just six equilateral triangles.

Setting the areas equal, we get:

$s_t^2 = 6s_h^2$

$\left(\frac{s_t}{s_h}\right)^2 = 6$

$\frac{s_t}{s_h} = \sqrt{6}$, and the answer is $\boxed{C}$.


See also

1998 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 14
Followed by
Problem 16
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