(1)DF⊥AB, the vertical foot is d, AD= 1, and the three angles of equilateral △ABC are 60 degrees, which can be calculated.

DN= radical number 3, NF=BD-DN=AB-AD-DN=3+ radical number 3- 1- radical number 3=2.

(2) Angle F= Angle A=60 degrees, Angle sum = Angle MNF=30 degrees, we can get

MN= root number 3, MF= 1.

So the area of the triangle MNF = 1/2* 1* root number 3= 1/2 root number 3.

Area of overlapping part =S- 1/2 root number 3