In triangle ABC, angle A = 20 degrees, angle B = 100 degrees. Point D is marked on the side AB
| September 21, 2021 | education
In triangle ABC, angle A = 20 degrees, angle B = 100 degrees. Point D is marked on the side AB so that the angle ACD = 40 degrees. Find the angle BCD.
In the ACD triangle, the angle ADC = (180 – BAC – ACD) = (180 – 20 – 40) = 120.
The angle ADC is the outer angle of the triangle BCD, then the angle ADC = (CBD + BCD).
Angle ВСD = АDС – CBD = 120 – 100 = 20.
Answer: The BCD angle is 20.
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