Help im doing a test its for most of my grade

Is the orthocenter of a triangle on the inside ?

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

In the diagram below? p is circumscribed about quadrilateral abcd. what is the value of x