Answer: C) 63
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Explanation:
Arcs CBH and FGH are given, while arc CDF is unknown. Let's call this y
y = measure of arc CDF
Adding the three arcs forms a full circle of 360 degrees
(arc CBH)+(arc FGH)+(arc CDF) = 360
170+64+y = 360
y+234 = 360
y = 360-234
y = 126
arc CDF = 126 degrees
Then notice how inscribed angle x cuts off arc CDF. By the inscribed angle theorem, we take half of the arc measure to get the inscribed angle measure.
inscribed angle = (arc measure)/2
x = (arc CDF)/2
x = 126/2
x = 63
