Question

Part of a single rectangular loop of wire with dimensions shown in the figure (Figure 1) is situated inside a region of uniform magnetic field of 0.561 T . The total resistance of the loop is 0.500 Ω

https://session.masteringphysics.com/problemAsset/1097229/3/GIANCOLI.ch21.p15.jpg

Calculate the force required to pull the loop from the field (to the right) at a constant velocity of 1.71 m/s . Neglect gravity.

My question is: Why is the length the 0.350m and not the 0.750m