Answer:
x=16
Step-by-step explanation:
the angle would be 1/2 of the arc so here's the steps
(2)7x+16=18x-32
14x+32=18x-32
+32 +32
14x+64=18x
-14x . -14x
64=4x
64/4=4x/4
x=16
Answer: 14.7338936% decrease

cross-multiply
85.2661064 = x
100 - 85.2661064 = 14.7338936
Check: 0.852661064 * 5355 = 4566
If permitted, you may round for a simpler (yet less precise and exact) answer. For instance, rounding to the hundredths would make it ~14.73%.