These are the degrees because of the Triangle Sum Theorem which states that The sum of the measures of the angles in a triangle is 180°. So angle C for example is 27 because angle A is 53 and angle B is 100 add both of those and you get 153 so our equation would be 153+c=180, c being the angle, so then to solve this you do do 180-153 and that equals 27 so therefore, 153+27=180. This process applys to all the other angles as well ^w^
