1.25 is the length x of a side of the square. Think about it like this. Divide 25 by 16 and you get 1.5625. Then, you do that number squared. So, √1.5625. That gives you 1.25. Hope that helps! Good luck!
2*200*300=(200+x)(300+x) 120000=60000+200x+300x+x^2 x^2+500x-60000=0 (x+600)(x-100)=0 x=-600 or x=100 length is positive thus negative value is ignored. So answer is 100