Answer:
a = 65°
b = 25°
c = 25°
d = 75°
Explanation:
60 + a + 55 = 180 (Angles of a straight line)
a + 115 = 180
a = 180 - 115
a = 65°
a + b + 90 = 180 (Interior angles of a triangle add up to 180°)
65 + b + 90 = 180
b + 155 = 180
b = 180 - 155
b = 25°
b = c (Vertically opposite angles are equal)
c = 25°
d + 15 = 90 (Complementary angles)
d = 90 - 15
d = 75°
Hope this helped!
~AH1807
Peace!