RMO ( 2016 ) Triangle Vs Quadrilateral

Geometry Level 5

Let A B C ABC be a triangle. Let D , E D, E be a points on the segment B C BC such that B D = D E = E C BD = DE = EC . Let F F be the midpoint of A C AC . Let B F BF intersect A D AD in P P and A E AE in Q Q , respectively.

Determine the ratio of the area of the triangle A P Q APQ to that of the quadrilateral P D E Q PDEQ .

If this ratio can be expressed as p q \dfrac pq , where p p and q q are coprime positive integers, submit your answer as p + q p + q .


The answer is 20.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Ahmad Saad
Nov 8, 2016

Used the same method.

Niranjan Khanderia - 4 years, 7 months ago
William Isoroku
Nov 10, 2016

Without the loss of generality, construct an isosceles triangle on a Cartesian coordinate system with on vertex at the origin for simplicity. Represent each line as a function and the intersection of the lines to find the coordinates. Then the areas can be easily calculated. The triangle I constructed has coordinates ( 0 , 0 ) , ( 6 , 0 ) , ( 3 , 6 ) (0,0),(6,0),(3,6) the coordinates of intersection turns out to be nice fractions and areas are easy to compute as well.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...