Question 1073876
Let w be the width of the rectangle. Then its length would be 3w+4. The area of the square would be (3w+4)². So:
w(3w+4)+66=(3w+4)²
3w²+4w+66=9w²+24w+16
6w²+20w-50=0
3w²+10w-25=0
(3w-5)(w+5)=0
w=5/3 or -5
The width is 1-2/3 cm, the length is 9 cm. ☺☺☺☺