Answer:
you need to place the centre of your protractor on the vertex of the two lines.
Step-by-step explanation:
Once you place it on the vertex, since the horizontal line is on the left side of the protractor, you start measuring the angle from the left side.
You keep on measuring the point where 2nd line overlaps some angle marking on the protractor.
For the bottom left angle, you need to place the protractor diagonally on the right most line as the horizontal line and then measure the angle.
