Use the animation below to explore and review the differences between acute and obtuse angles. Use the checkboxes to make the examples visible or invisible. Use the sliders to adjust and change the angles.

Use the animation below to explore reflex angles.

Straight angles are the angles formed by three points on a straight line. The angle is equal to 180[math]^\circ[/math]. Right angles have a value of 90[math]^\circ[/math] and they resemble a corner.

A revolution is a 360[math]^\circ[/math] angle - one complete revolution or full circle.