In figure ∠ABC = 69∘, ∠ACB= 31∘, find ∠BDC. - Sri Chaitanya Infinity Learn Best Online Courses for NCERT Solutions, CBSE, ICSE, JEE, NEET, Olympiad and Class 6 to 12

By angle sum property of triangle we have
∠BAC + ∠ABC + ∠ACB =

180^{\circ}

\Rightarrow

∠BAC +

69^{\circ}

31^{\circ}

180^{\circ}

⇒ ∠BAC =

80^{\circ}

∠BAC and ∠BDC are angles subtended by chord BC on the arc of a circle.
⇒ ∠BDC =

80^{\circ}

So, Option 2 is correct.

In figure ∠ABC = $69^{\circ}$ , ∠ACB= $31^{\circ}$ , find ∠BDC.