The second problem was Euclid 's theory of proportion, derived from Eudoxus . Robert Simson of Glasgow University had, in his 1756 edition of the Elements, given a proof of the parallel axiom based on another assumption.
Ang pangalawang problema ay Euclid 's theory ng katapat, nagmula sa Eudoxus. Robert Simson ng Glasgow University had, sa kanyang 1756 edition ng Sangkap, bibigyan ng isang patunay ng pagpaparis axiom batay sa ibang palagay.