1. If angle DAC is x, then Angle GMC=Angle EFG=Angle BDF=x 2. Then angle EO2G=2x; Angle O1OC=2x (According to the rule that the central angle is two times that of peripheral angle on a circle) 3. According to the same rule angle GO3C=2x= angle BO1O2; then Angle OO1O2= Angle GO3O=180-2x 4. Because alternate angles are same; the O1OO3O2 is a parralelogram
1. If angle DAC is x, then Angle GMC=Angle EFG=Angle BDF=x
ReplyDelete2. Then angle EO2G=2x; Angle O1OC=2x (According to the rule that the central angle is two times that of peripheral angle on a circle)
3. According to the same rule angle GO3C=2x= angle BO1O2; then Angle OO1O2= Angle GO3O=180-2x
4. Because alternate angles are same; the O1OO3O2 is a parralelogram