< a = 60....because < a is congruent to < b because they are vertical angles
< b = 60..because < b is congruent to the 60 degree angle
< c = 70...because < c is congruent to the 70 degree angle
< d = 180 - (70 + 60) = 180 - 130 = 50 ...because the interior angles of a triangle = 180 degrees