In an isosceles triangle ABC with the base AC, the bisector BM is drawn. Find the angle MBC if the angle A is 50 °

Triangle ABC is isosceles, AC is the base, so angle A is equal to angle C:

A = C = 50 °.

The MBC angle is equal to the ABM angle (BM is the bisector):

MBC = ABM = ABC: 2

The angles in a triangle add up to 180 °.

Find the angle ABC

ABC = 180 ° – 2 × 50 °;

ABC = 180 ° – 100 °;

ABC = 80 °.

Find the MBC angle:

MBC = ABC: 2;

MBC = 80 °: 2;

MBC = 40 °.