In an isosceles triangle ABC (AC-Base), the bisector of the angle A-ray AD is drawn. Find the outer angle
April 2, 2021 | education
| In an isosceles triangle ABC (AC-Base), the bisector of the angle A-ray AD is drawn. Find the outer angle of the triangle at the vertex C, if the angle BAD = 35.
Since, by condition, AD is the bisector of the angle ABC, then the angle ABC = 2 * BAD = 2 * 35 = 70.
The ABC triangle is isosceles, then its angles at the base of the AC are equal, the angle BAC = BAC = 70.
The outer angle BCE, at the vertex C, adjacent to the inner angle of the BCA, the sum of which is 180, then the angle BCE = (180 – BCA) = 180 – 70 = 110.
Answer: The outer angle at the vertex C is 110.
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