A theorem of Bender states
that if a convex figure F contains no point of the two dimensional lattice G,
where G is generated by the vectors V1 and V2 having enclosed angle 𝜃, then
A(F) ≦ 1∕2P(F)max(|V1|,|V2|sin𝜃) where |V1|≦|V2|. In this paper, two
questions are answered: (1) Among all convex figures of perimeter L which are
admissible relative to a rectangular lattice G, which encloses the maximum
area? (2) Can the constant 1/2 in Bender’s theorem be improved? By using
the result of (1), the “sharpest possible” inequality of the Bender type is
found.