Answer: B. 141
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Step-by-step explanation:
The arc measures of 60 and x average to the angle 70, which is the the angle formed between the intersecting chords
70 = (60+x)/2
70*2 = 60+x
140 = x+60
x+60 = 140
x = 140-60
x = 80
The full 360 degree circle has the arc measures of 60, 79, x = 80, and w, where we don't know w yet. But we can add the four pieces of the circle to get 360
60+79+x+w = 360
60+79+80+w = 360
w+219 = 360
w = 360-219
w = 141
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Or you could find angle z first
z+70 = 180
z = 180-70
z = 110
Then use the averaging technique done at the start of this problem
z = (79+w)/2
110 = (79+w)/2
2*110 = w+79
220 = w+79
w+79 = 220
w = 220-79
w = 141