Bisector BD is drawn in triangle ABC, angle ADB = 120 °, angle B = 80 ° find the angles of triangle CBD.
April 26, 2021 | education
| 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 °.
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