Answer:
A) 60°
B) 45°
C) 50°
Step-by-step explanation:
the sum of the internal angles of a triangle is 180 °, so the first is an equilateral triangle, so all angles are 60 °.
the second is a right isosceles triangle with an angle of 90 ° and two angles of 45 °.
the third is a right triangle with an angle of 90 °, one from 40 ° and x is 50 °.
