You can put this solution on YOUR website! a square has all equal sides
so let x=the value of a side
and to make this an easy value we will say x=10
so if x=10 then the area of the square would be 100
so 100% of 10 is 10 and 150% of 10 is 15
so if we increased x by 150% then x+15=25 and 25*25=625 so all u need to find is what percentage from 100 to 625 which is % "area increased"
(If u need to see the math it would be 100/100=1 and 625/100=6.25 so 6.25 times 100%=625% this is why i used 10 as the sides so I wouldnt need to do this math.)