Question

Q.17. ACD is an exterior angle of triangle ABC. If angle A = 50°, then find angle
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Answer 1

Step-by-step explanation:

Let ∠A = 2x∘.

Then ∠B = (4x)∘; ∠C = (5x)∘ and ∠D = (7x)∘

Since the sum of the angles of a quadrilateral is 360o, we have:

2x + 4x + 5x + 7x = 360∘

⇒ 18 x = 360∘

⇒ x = 20∘

∴ ∠A = 40∘; ∠B = 80∘; ∠C = 100∘; ∠D = 140∘