# Given: triangle ABC, angle ABD = 20 degrees, angle A = 40 degrees BD – bisector Find: angle C.

July 24, 2021 | education

| By definition, the bisector in a triangle divides the angle into two equal parts, then BD divides the angle B in half:

<ABD = <DBA = 20 °.

The sum of all angles in a triangle is 180 °. Find the degree measure of the angle C:

<C = 180 ° – <A – (<ABD + <DBA);

180 ° – 40 ° – (20 ° + 20 °) = 100 °.

Answer: <C = 100 °.

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