Answer :
Each segment is = 2 in
I have half of AB, all BC segment and half of CD, so:
1/2*2+2+1/2*2=1+2+1=4
MN=4in
I have half of AB, all BC segment and half of CD, so:
1/2*2+2+1/2*2=1+2+1=4
MN=4in