2015 AIME II Problems/Problem 4
Problem
In an isosceles trapezoid, the parallel bases have lengths and
, and the altitude to these bases has length
. The perimeter of the trapezoid can be written in the form
, where
and
are positive integers. Find
.
Solution
Call the trapezoid with
as the smaller base and
as the longer. The point where an altitude intersects the larger base be
where
is closer to
.
Subtract the two bases and divide to find that is
. The altitude can be expressed as
. Therefore, the two legs are
, or
.
The perimeter is thus which is
. So
See also
2015 AIME II (Problems • Answer Key • Resources) | ||
Preceded by Problem 3 |
Followed by Problem 5 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
All AIME Problems and Solutions |
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