one of the base angles of an isosceles triangle is 70 . the vertical angle is

**Given :** One of the base angle of an isosceles triangle is 70°

⇒ Other base angle of the isosceles triangle = 70°

Now, we know that the sum of the measure of all the angles of a triangle is 180°

⇒ One base angle + other base angle + vertical angle = 180°

⇒ 70° + 70° + vertical angle = 180°

⇒ 140° + vertical angle = 180°

⇒ vertical angle = 180° - 140° = 40°

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