Math Prize 2010 Problem 19
Source:
November 14, 2010
geometrysymmetryprobabilityexpected value
Problem Statement
Let be the set of 81 points such that and are integers from through . Let , , and be random points chosen independently from , with each of the 81 points being equally likely. (The points , , and do not have to be different.) Let be the area of the (possibly degenerate) triangle . What is the expected value (average value) of ?