Question

Is it possible to form a square whose area is 18 by connecting four lattice points? Explain.

Answer 1

note the squares... 13 is possible because it is a sum of two squares (integers) 9 + 4 .. use (0,3) & (2,0) ... get the square roots and place on different coordinate axes... for a simpler value. but there is none for 15... there is one for 18 ... 18 = 3^2 + 3^2 ... try (0,3) ,(3,0) , (3,6), (6,3).