Respuesta :

so if you want to find x then all you have to do is follow this 
(20x + 10)/2 = 16x - 1
10x + 5 = 16x - 1 
6x = 6
x = 1   
Angle at centre = 2 * Angle at circumference.

Angle at centre = 20x + 10

Angle at circumference = 17x - 2

20x + 10 = 2*(17x - 2)
20x + 10 = 2*17x - 2*2
20x + 10 = 34x - 4
20x - 34x = -4 - 10
-14x = -14

x = -14/-14
x = 1.

1st Option.