Canada Post accepts international parcels whose (Length + Girth) ≤ 2 meters, and Length ≤ 1 meter. Girth is defined as the perimeter of the cross-section.
We wish to ship a parcel of the shape of a triangular prism of length l meters. The cross-section is a right triangle with catheti of lengths a and b meters. Assume the package walls thin. What is the maximal possible volume of such a parcel?

Question