Because AB=AD
Angle A=60 degrees
So triangle ADB is an equilateral triangle.
So AB=BD
Angle ABD= Angle ABE+ Angle DBE=60 degrees.
Because the line segment BE rotates counterclockwise around the point e by an angle α.
So the angle BEF=60 degrees
BE=EF
So the triangle BEF is an equilateral triangle.
So BE=BF
Angle EBF= Angle DBE+ Angle DBF=60 degrees.
So angel Abel = angel ·DBF
So triangle Abbe and triangle DBF are congruent (SAS)
So AE=DF
2. Solution: Because the angle D= 1/2 and the angle A+90 degrees.
Because the angle α= 60 degrees
So the angle D= 120 degrees.
So angle ADE+ angle DAB= 180 degrees.
So parallel AB
So angle FCM= angle MAB
Angle MFC= Angle MBA
So the triangle MFC is similar to the triangle MBA (AA).
So CF/AB=FM/BM
Because triangle AEB and triangle DFB are congruent (proved)
So the triangle of AFB = the triangle of DFB.
Because AE/DE= 1/2.
So the S triangle AEB/S triangle DEB= 1/2.
So s triangle DFB/S triangle DEB= 1/2.
Because the area of quadrilateral DEBF =S triangle DEB+S triangle DFB=9 times the root number 3/4.
So the s triangle AEB=E times the root number 3/4.
Because the angle of the S triangle AEB =1/2 * AE * AB * Sindab =1/2 * AE * AB * Sin60.
Because AD=AE+DE=AB (authentication)
Because AE/DE= 1/2.
So AE/AB= 1/3.
So: 3 times the root number 3/4= 1/2*AE*AB*sin60.
So AE= 1
AB=3
Because CF= 1/2
So CF/AB= 1/6.
So FM/MB= 1/6.
So BM/BF=6/7.
In triangle AEB, it is obtained by cosine theorem:
BE^2=AE^2+AB^2-2*AE*AB*cos60
So BE= root number 7
Because BE=BF (confirmed)
So BF= root number 7
So BM=6 times the root number 7/7.