Answer:
Step-by-step explanation:< at center is twice angle at circumfrence. where the dot is. drawing an angle of 108 degrees.
108/2=54
y and w=54.
to get z
40 +108 +2A=360(<at a point)
148+2a=360
2a=360-148
a=360-148/2=106
106 +w+z=180 <on a straight line
106+54+z=108
160+z=180
z=180-160
=20