The vertical angle A of an isosceles triangle ∆ABC

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The vertical angle A of an isosceles triangle ∆ABC is three times the angle B of it. The measure of the angle A is

As per the given in question , we draw a figure of an isosceles triangle ABC

In ∆ABC,
AB = AC
∴ ∠B = ∠C
∵ ∠A + ∠B + ∠C = 180°

∴ ∠A +	∠A	+	∠A	= 180°
	3		3

⇒	3∠A + ∠A + ∠A	= 180°
	3

⇒	5∠A	= 180°
	3

⇒ ∠A =	180° × 3	= 108°
	5