We measure an angle using these steps, always in this order: Step 1: Place the centre mark exactly on the vertex of the angle. Step 2: Turn the protractor so the zero line lies along one ray of the angle. Step 3: Follow the other ray out to the scale and read the number where it crosses - using the scale that starts at 0 on the side of your zero line. Reading for this angle: the ray passes through the mark labelled 60 on that scale, so the angle measures 60°. Sanity check (never skip it): 60° is less than 90°, so the angle should look narrower than a book corner - it does. Say it plainly: centre on the vertex, zero on a ray, read from zero. Two placements, then one reading.

The protractor is placed correctly: centre on the vertex, zero line along the bottom ray. The top ray passes through the mark labelled 75 on the scale that starts at 0. What is the measure? -> 75°