Find dimensions of a parcel using length left of a surrounding rope A parcel has the form of a cuboid. The picture below shows a rope of 1.9 m wound around this parcel in three different ways. ![3 cases with the rope around the parcel]( In the first case 0.6 m is left for the knot. In the second case one has 0.2 m for the knot and in the third case 0.5 m. By using the following data, the dimensions of the parcel should be found. This exercise is totally blocking me. My first thoughts were to find a system of equations and then solve it, but I don't know how to apply it to the following case.

By seeing the 3 cases, I finally found a system of equations to solve (x the length, y the width and z the height) :

_2x + 2y + 4z = 1.3_

_4x + 2y + 2z = 1.7_

_2x + 4y + 2z = 1.4_

I solved the system by using the substitution method and I got then the following solutions :

_x = 0.3_

_y = 0.15_

_z = 0.1_