Question

Q1. In the given figure, ABCD is a parallelogram. Complete each statement along with the definition or property used.

(i) AD = ……….. (ii) DC = ……….. (iii) ∠DCB = ………..
(iv) ∠ADC = ……….. (v) ∠DAB = ……….. (vi) OC = ………..
(vii) OB = ……….. (viii) m∠DAB + m∠CDA = ………..

Answer 1

Explanation:

i. AD = BC= 6cm (each two opposite sides are equal in length in parallelogram)

ii.DC=AB=9cm (each two opposite sides are equal in length in parallelogram)

iii.DCB=60 ,, bec DC and AB are parallel so their interior angles are supplementary their sum equals 180°

so DCB = 180-120=60°

iv.ADC=ABC = 120° because each two opposite angles are equal in measure in parallelogram

v. DAB=DCB =60° because each two opposite angles are equal in measure in parallelogram

vi. OC=AO =7cm because the diagonals of parallelogram bisect each other

vii. OB=DO=5cm because the diagonals of parallelogram bisect each other

viii . DAB=60° ,, CDA= 120 °

DAB+CDA =180°

or you could simply say that because DC and AB are parallel their interior angles are supplementary their sum is 180°