A bisector is a ray that comes out of an angle and divides that angle into two equal angles. In a triangle ABC, AD is the bisector. Based on the definition and knowing that the CAD angle is 39 °, we find the angle A. 39 ° * 2 = 78 °.
By the theorem, the sum of the angles of the triangles is 180 °. Based on the theorem, we find the angle B. Angle B is equal to 180 ° – (A + C).
Solution: 180 ° – (78 ° + 53 °) = 49 °. Angle B is 49 °.
Answer: 49 °.
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