**Drag the vertex of the angle to place the vertex at point $\text{A}$.** **Drag another point on the angle to make one of the rays go through point $\text{B}$.** **Make the other ray go through one of the unlabeled black points to create a right angle.** *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]] $90^\circ$.