In the diagram below, O is circumscribed about quadrilateral DEFG. What is the value of x?

Answer:
A. 70
Step-by-step explanation:
The given quadrilateral DEFG is a cyclic quadrilateral.
[tex]\angle F+70\degree=180\degree[/tex]...opposite angles of a cyclic quadrilateral are supplementary.
[tex]\implies \angle F=180\degree-70\degree[/tex]
[tex]\implies \angle F=110\degree[/tex]
The sum of angles in a quadrilateral is 360 degrees.
[tex]x-10+70+110+120=360[/tex]
[tex]x+290=360[/tex]
[tex]x=360-290[/tex]
[tex]x=70\degree[/tex]