Area of equilateral triangle of side a,
A=21×a×23a=43a2
Magnetic moment of each triangle,
m=IA=43a2I
12a length of wire will form 4 loops of triangle of side a.
Magnetic moment of triangle,
M1=Nm=4×43a2I=3Ia2
Similarly, magnetic moment of square
M2=Nm=3×(Ia2)
=3Ia2