SOLUTION: ABC is a triangle. find the unknown angle A=60degree B=70degree C=30degree Dwhich is x=?

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Question 821478: ABC is a triangle. find the unknown angle
A=60degree
B=70degree
C=30degree
Dwhich is x=?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

given:
ABC is a triangle
A=60+degree
B=70 degree
C=30 degree
D=+x
solution:
start with definition: the sum of all angles in triangle is 180 degrees
as you can see, angle x is part of either angle A,angle B, or
angle C
then we have
A%2BB%2BC%2Bx=180.....plug in given values
60%2B70%2B30%2Bx=180.....solve for x
160%2Bx=180
x=180-160
x=20...............the unknown angle