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

(Created page with "== Problem 15 == 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?...")
 
 
(One intermediate revision by one other user not shown)
Line 1: Line 1:
== Problem 15 ==
+
== 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]]
+
==Solution==
 +
 
 +
<math>A_{\triangle} = \frac{s_t^2\sqrt{3}}{4}</math>
 +
 
 +
<math>A_{hex} = \frac{6s_h^2\sqrt{3}}{4}</math> since a regular hexagon is just six equilateral triangles.
 +
 
 +
Setting the areas equal, we get:
 +
 
 +
<math>s_t^2 = 6s_h^2</math>
 +
 
 +
<math>\left(\frac{s_t}{s_h}\right)^2 = 6</math>
 +
 
 +
<math>\frac{s_t}{s_h} = \sqrt{6}</math>, and the answer is <math>\boxed{C}</math>.
 +
 
 +
 
 +
 
 +
== See also ==
 +
{{AHSME box|year=1998|num-b=14|num-a=16}}
 +
{{MAA Notice}}

Latest revision as of 13:29, 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
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
All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png