"Of trilateral figures, an equilateral triangle is that which has its three sides equal, an isosceles triangle that which has only two of its sides equal, and a scalene triangle that which has its thre…"

"The greatest of the parts is called the antecedent, and the less the consequent."

"In any right-angled triangle, the square on the side subtending the right angle is equal to the squares on the sides containing the right angle."

"There are infinitely many prime numbers."

"Parallel straight lines are straight lines which, being in the same plane and being produced indefinitely in both directions, do not meet one another in either direction."