Copy the shape and fill in the missing angle. Sow the work. Thanks.

Answer:
x = -11
Step-by-step explanation:
Hello There!
create an equation
x + 51 + 60 + 80 = 180
combine like terms
51 + 60 + 80 = 191
x + 191 = 180
subtract 191 from each side
180 - 191 = -11
we're left with
x = -11