MathDB
Cube problem

Source: 2015 BAMO-12 #4

February 22, 2016
geometry3D geometrycube

Problem Statement

Let AA be a corner of a cube. Let BB and CC the midpoints of two edges in the positions shown on the figure below: http://i.imgur.com/tEODnV0.png The intersection of the cube and the plane containing A,B,A,B, and CC is some polygon, PP.
[*] How many sides does PP have? Justify your answer. [*] Find the ratio of the area of PP to the area of ABC\triangle{ABC} and prove that your answer is correct.