What is the sum of the angles at a point ?

Q. The sum of the angles at a point is

Q. When two lines intersect at a point, what is the sum of the measures of both pairs of vertical angles?

Q. What is the sum of all the angles of a 9 pointed star $(i.e.,\angle 1+\angle 2+\angle 3+\dots \angle 8+\angle 9)$:

Q. The locus of the point of intersection of tangents to an ellipse at two points, sum of whose eccentric angles is constant is a/an:

Q.

If the sum of the two angles of a quadrilateral is ${180}^{\circ },$ What is the sum of the remaining two angles?