Q8 of 35 Page 3

ABCD is a ||gm with ∠ A = 800. The internal bisectors of ∠ B and ∠ C meet at O. Find the measure of the three angles of Δ BCO.


∠ C = ∠ A (Opposite angles of a ||gm are equal) ∠ C = 800 (Given ∠ C = 800)∠ OCB = = = 400
∠ B = 1800 - ∠ A (Sum of interior angles on the same side of the transversal is 1800 )
= 1800 - 800
= 1000 ∠ CBO = = = 5O0 ∠ BOC = 1800 – (∠ OBC + ∠ CBO) (Angle sum of a Δ ) = 1800 – (400 + 500) = 1800 - 900 = 900 ∴ The Three angles of the triangle BCO namely ∠ OCB, ∠ CBO, ∠ BOC are 400, 500 and 900 respectively.

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