Find the value of each variable. for each circle, the dot represents the center

We know that
The inscribed angle measures half of the arc it comprises.
Opposite angles in a cyclic quadrilateral add up to 180°

Part 1)
a=360-(128+134)> a=98°
b=a/2> b=98/2> 49°

the answer Part 1) is
a=98°
b=49°

Part 2)
92+d=180> d=180-92> d=88°
102+c=180> c=180-102> c=78°
140+a=102*2> a=204-140> a=64°
b+a=2*d> b+64=2*88> b=2*88-64> b=112°

the answer Part 2) is
a=64°
b=112°
c=78°
d=88°

A) for the n row: 22+(n-1)×6therefore,b) 100-22=78that means (n-1)×6=7878÷6=1313+1=1414th row has 100 seats