Ato H. answered 12/06/12
Reliable, Erudite Math, Science & GED Tutor.
The answer below is totally wrong!! How can the diagonal have a greater magnitude than the Area. You solve it like this instead :
First find the length of each side of the square by: √(Area)= Length of each side of square, which is √16 = 4 cm
Now divide the square into two isosceles right triangles with the diagonal.
Working on one of the triangles, apply Pythagorean Theorem i.e.
(Diagonal)2 = (4)2 + (4)2 the 4's come from the sides of the square that no form two equal sides of i the isosceles right triangle
so (Diagonal)2 = 32
√(Diagonal)2 = √(32)
Diagonal= 4√2 cm OR
≈5.65685424949 cm :-)