Answer:
A) 150
Step-by-step explanation:
All the angles in a triangle must add up to a total of 180 degrees.
So we can make an equation as given below:
20+10+?=180
30+?=180
?=150
So the missing angle is 150 degrees
150
Subtract 20 and 10 to 180 because the side of a triangle(or all three sided figures) is 180 and you get 150
