Question

in a triangle  ABC ,AB = AC , angle BAC = 40, then external angle at  B is ???

Answer 1

Hi friend
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Your answer
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In ∆ABC,

Given that : - AB = AC. Angle BAC = 40°.

To calculate : - External angle ag B.

Now,
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Angie ABC = Angle ACB [ Because AB = AC.]

So,
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Angle ABC = (180° - Angle BAC)/2 = (180° - 40°)/2 = 140°/2 = 70°

Therefore,
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External angle at B = (180° - 70°) = 110°.

HOPE IT HELPS