Refer to the attached image.
Given: and measure of exterior angle at C =
.
We have to determine the measure of angle B and angle BCA.
By applying exterior angle property of the triangle which states:
"An exterior angle of a triangle is equal to the sum of the opposite interior angles".
So, exterior angle C =
Now, applying angle sum property in triangle ABC which states:
"The sum of all the angles of a triangle is 180 degrees".
Therefore, the measure of and
.
