Question

for what value of x in the figure points A,B,C,D are concyclinc

Answer 1

89+81+x=180
170+x=180
x=180-170
x=10

Answer 2

According to the rule,

=>The sum of Opposite angle of an concyclic quadrilateral is 180

applying this here,

89+81+x=180

170+x=180

x=180-170

x=10