2018 AIME I Problems/Problem 2
Problem
What is the area of the polygon whose vertices are the points of intersection of the curves 
and 
Solution
The first curve is a circle with radius 
centered at the origin, and the second curve is an ellipse with center 
and end points of 
and 
. Finding points of intersection, we get , 
, and 
, forming a triangle with height of 
and base of 
So the area of this triangle is $9 \cdot 6 \cdot 0.5 =27 $
