MathDB

5

Part of 2019 Novosibirsk Oral Olympiad in Geometry

Problems(1)

BD + BA = AC if <B=3<C, <BDC=2<C (2019 Novosibirsk Oral Geo Oly 7.5)

Source:

4/26/2021
Given a triangle ABCABC, in which the angle BB is three times the angle CC. On the side ACAC, point DD is chosen such that the angle BDCBDC is twice the angle CC. Prove that BD+BA=ACBD + BA = AC.
geometryequal angles