2021 AMC 10A Problems/Problem 21
Problem 21
Let be an equiangular hexagon. The lines
and
determine a triangle with area
, and the lines
and
determine a triangle with area
. The perimeter of hexagon
can be expressed as
, where
and
are positive integers and
is not divisible by the square of any prime. What is
?
Solution (Misplaced problem?)
Note that the extensions of the given lines will determine an equilateral triangle because the hexagon is equiangular. The area of the first triangle is , so the side length is
. The area of the second triangle is
, so the side length is
. We can set the first value equal to
and the second equal to
by substituting some lengths in with different sides of the same equilateral triangle. The perimeter of the hexagon is just the sum of these two, which is
and
Video Solution by OmegaLearn (Angle Chasing and Equilateral Triangles)
~ pi_is_3.14