If the side of a square increases by 40%, then the area of the square increases by?

Suppose the length of a square is s. The area of such a square is given by

A =  s²

If s is increased by 40%, the resulting length will be (s + 0.40s)  = 1.40s. Thus, the area of the new square will be

A' = (1.40s)(1.40s) = 1.96s²

Note that we can rewrite as

A' = s² + 0.96s²

This is mathematically equivalent to the original area, s²,  increasing by 96%.

Hope this helps!