Answer:
x = 8
Explanation:
The measure of an arc is equal to the angle at the centre subtended by the arc.
The sum of the 3 arcs = 180° , then
5x + 6 + 83 + 51 = 180
5x + 140 = 180 ( subtract 140 from both sides )
5x = 40 ( divide both sides by 5 )
x = 8