Step-by-step explanation:
answer 1) 122°
using angles sum property of a triangle:
65°+57°+x=180°
x=180-(65+57)
=122°
2) 50°
using angles sum property of a triangle:
90°+40°+x=180° (since shown right angled triangle)
x=180-(90+40)
=50°
similarly,3) 30°
4) 45°
