The second time, because it is 30% off, the rope length =3 weeks +4.5 meters.
That is, 4 weeks +2 meters =3 weeks +4.5 meters,
In fact, it is to solve the equation and let a circumference be x meters.
4x+2=3x+4.5
x=2.5
4x+2= 12
Answer: The length of the rope is12m, and the circumference of the circle is 2.5m..