Question

Diagonals of parallelogram ABCD intersect each

other at point O. If ADO = 60ᵒ, ABO = 40ᵒ and

OAB = 30ᵒ, then find the measure of BCD,

COD, OCB.​

Answer 1

angle BDC=angle ABD=40 degree(alternate interior angles) , angle CBD=angle ADB=60°

angle DCA=angle CAB=30°

we know sum of angles of a parallelogram is 360°

therefore, angle dac and angle bca = 360- sum of the given angles

=360-260=100

angle BCA= angle DAC =100/2= 50°