Question 1099264
2+2(0.5) = 3 this is the long side of the triangle and also the sides of the square.
(3+x)*(3+x) = 81
(3+x)^2 = 81
3+x = 9
x = 6 so you have to add 6 to each side of the square. In percent:
6/3 = 2; 2*100 = 200 
you have to increase the side of the square by 200%