In the adjoining figure, is a parallelogram in which
and
Calculate (i) (ii)
(iii)
(iv)
In ABCD,
and
(i) In ∆AOB,
∠BAO = 35°
∠AOB = ∠COD = 105° …Vertically opposite angels
∴ ∠ABO = 180° − (35° + 105°) = 40° … Using Angle sum property of Triangle
(ii) ∠ODC and ∠ABO are alternate angles for transversal BD
∴ ∠ODC = ∠ABO = 40°
(iii) ∠ACB = ∠CAD = 40°° …Alternate angles for transversal AC
(iv) ∠CBD = ∠ABC − ∠ABD ...(1)
∠ABC = 180° − ∠BAD …Adjacent angles are supplementary
∠ABC = 180° − 75° = 105°
∠CBD = 105° − ∠ABD … as ∠ABD = ∠ABO
∠CBD = 105° − 40° = 65°