The difference between the supplementary angle and the complementary angle of any acute angle is............. (in $^{\circ}$)

$\angle ACD$ is an exterior angle of $\Delta ABC$. The bisector of $\angle ABC$ and exterior $\angle ACD$ intersect each other at point $E$. Prove that,$\angle BEC = \frac{1}{2} \angle BAC$.

If two interior angles on the same side of a transversal intersecting two parallel lines are in the ratio $2:3,$ then the greater of the two angles is (in $^{\circ}$)

For what value of $x+y$ in the figure will $ABC$ be a straight line? Justify your answer.

Find the measure of the complementary angle of the supplementary angle of an angle having measure $128^{\circ}$. (in $^{\circ}$)

If one of the angles formed by two intersecting lines is a right angle,what can you say about the other three angles? Give reason for your answer.