To answer this question you will use the
Pythagorean Theorem. a^2+b^2=c^2. In this
case a and b are the same because it is a
square. So 2x^2=1600 (c^2 where c=40).
Solve this equation ( divide both sides by two
and find the square root for both). Each side
length should be approximately 28.3 cm.