Bisector BD is drawn in triangle ABC, angle ADB = 120 °, angle B = 80 ° find the angles of triangle CBD.

In this task, we will find the angles of the CBD triangle;

To do this, recall the properties of the angles of a triangle;

In any triangle, the sum of all its angles is 180 °;

Consider the resulting triangle ADB. We know the angle ADB and the angle B, which the bisector divided by the palms, we write the equation of the angles;

A + ADB + B / 2 = 180;

Let’s substitute the data;

A + 120 + 80/2 = 180;

Find the value of the angle A;

A = 180 – 120 – 40 = 20 ° – the value of the angle A;

Find angle C from triangle ABC;

180 = A + B + C;

180 = 20 + 80 + C;

C = 80 °;

Consider a CBD triangle and write down the sum of its angles;

180 = C + B / 2 + CDB;

180 = 80 + 80/2 + CDB;

CDB = 60 °;

Angles of triangle CBD;

80 °, 60 °, 40 °.