Question

Please answer this one..Thanks

Answer 1

We know that
In a rectangle diagonal bisect each other.

So OD = OA = OC = OB

a) So, Angle ADO = DAO...... (i)

DOA + BOA = 180° { linear pair}
DOA + 80° = 180°
DOA = 180 - 80
DOA = 100°

In ∆ AOD
DOA + ADO + DAO = 180° { angle sum property of ∆}

100 + ADO + ADO = 180° { From eqn i}
2 ADO = 180 -100
2 ADO = 80
Angle ADO = 80/2
ADO = 40°



b) In ∆ DOC
DOC = AOB { linear pair}
DOC = 80°

DCA = CDB ...... (ii)

DOC + DCA + CDB = 180° { angle sum property of ∆}
80° + DCA + DCA = 180° { from eqn ii}
2 DCA = 180-80
2 DCA = 100°
DCA = 100/2
DCA = 50°


Hope it helps u.