**Make a right angle by using the three black points as follows.** **Drag the vertex of the angle to place the vertex at the correct black point.** **Drag the points on the rays to make the rays go through the other two black points.** *The arc symbol near the vertex will show the right angle symbol when the angle is correct.* [[☃ interactive-graph 1]] This is a right angle because its measure is [[☃ dropdown 1]] $90$ degrees.