Answer:
a + b + c + d = 230
Step-by-step explanation:
So first, I am going to write down everything that I can find out from the picture.
a + b = 115
c + d + (180 - a) + (180 - b) = 360
Now, I can use a + b = 115 to simplify c + d + (180 - a) + (180 - b) = 360.
c + d + (360 - (a + b)) = 360
c + d + (360 - 115) = 360
c + d +245 = 360
c + d = 115
Now I know that:
a + b = 115
c + d = 115
Now I can find a + b + c + d
a + b + c + d = (a + b) + (c + d) = 115 + 115 = 230
a + b + c + d = 230