Percentage change in area of two dimensional figure

If all the measuring sides of any two dimensional figure is changed by x%, then its area changes by (2x + x²/100) %

Eg. If all the sides of a hexagon is increased by 5%, then the % change in area is:

x = 5

(2x + x²/100) %

(2 x 5 + 5²/100) %

= 10.25%