Difference between revisions of "2007 AMC 12B Problems/Problem 14"
Chickendude (talk | contribs) (New page: ==Problem 14== Point <math>P</math> is inside equilateral <math>\triangle ABC</math>. Points <math>Q</math>, <math>R</math>, and <math>S</math> are the feet of the perpendiculars from <mat...) |
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Point <math>P</math> is inside equilateral <math>\triangle ABC</math>. Points <math>Q</math>, <math>R</math>, and <math>S</math> are the feet of the perpendiculars from <math>P</math> to <math>\overline{AB}</math>, <math>\overline{BC}</math>, and <math>\overline{CA}</math>, respectively. Given that <math>PQ=1</math>, <math>PR=2</math>, and <math>PS=3</math>, what is <math>AB</math>? | Point <math>P</math> is inside equilateral <math>\triangle ABC</math>. Points <math>Q</math>, <math>R</math>, and <math>S</math> are the feet of the perpendiculars from <math>P</math> to <math>\overline{AB}</math>, <math>\overline{BC}</math>, and <math>\overline{CA}</math>, respectively. Given that <math>PQ=1</math>, <math>PR=2</math>, and <math>PS=3</math>, what is <math>AB</math>? | ||
− | <math>\mathrm {(A)} 4 | + | <math>\mathrm{(A)}\ 4 \qquad \mathrm{(B)}\ 3\sqrt{3} \qquad \mathrm{(C)}\ 6 \qquad \mathrm{(D)}\ 4\sqrt{3} \qquad \mathrm{(E)}\ 9</math> |
==Solution== | ==Solution== |
Revision as of 00:07, 21 February 2008
Problem 14
Point is inside equilateral
. Points
,
, and
are the feet of the perpendiculars from
to
,
, and
, respectively. Given that
,
, and
, what is
?
Solution
Drawing ,
, and
,
is split into three smaller triangles. The altitudes of these triangles are given in the problem as
,
, and
.
Summing the areas of each of these triangles and equating it to the area of the entire triangle, we get:
where
is the length of a side