Answer:
80
Step-by-step explanation:
All the angles of a triangle should add up to 180. So, 180 - 77 is 103. 103 - 23 is 80. The answer is 80.
77°+ 23°+angle b=180°[by angle sum property]
100°+angle b=180°
angle b=180°-100°
angle b=80°
