Question 53
(POL 2) Given two segments $AB$ and $CD$ not in the same plane, find the locus of points $M$ such that
$$ MA^2+MB^2=MC^2+MD^2. $$
$$ MA^2+MB^2=MC^2+MD^2. $$
IMO 1969 - Longlist Problems Question 53
IMO Shortlist · IMO 1969 - Longlist Problems