In this worksheet, you will need to know that certain angles are equal to each other when you draw a line across two parallel lines.
Look at the diagram below to see which of the 8 angles are equal to each other. All the "a" angles are equal and all the "b" angles are equal.
Remember also that aº + bº = 180º as they are the angles on a straight line.
Also remember that the angles in a triangle add to 180º.