The figure below is made up of a trapezium and 2 parallel lines. Study the figure and answer the following questions.

1. (a)

   which 2 angles add up to $75^\circ$?

   Ans: (a) $\angle$ ___ and $\angle$ ___

2. (b)

   which 2 angles add up to $165^\circ$?

   Ans: (b) $\angle$ ___ and $\angle$ ___