In the cyclic quadrilateral WXYZ on the circle centered at O, ∠ZYW=10∘ and ∠YOW=100∘. What is the measure of ∠YWZ?
In the cyclic quadrilateral WXYZ on the circle centered at O, ∠ZYW=10º and ∠YOW=100º. What is the measure of ∠YWZ?
When the quadrilateral is inscribed in a circle, the sum of the opposite angles is 180º.
If ∠YOW=100º then ∠WXY = 50º
If ∠WXY = 50º then the opposite angle (∠YWZ) must be 130º. 
