A straight-line angle is exactly 180°. It looks like a perfectly straight line, like the top of a table. A reflex angle is larger than 180° but smaller than 360°. It’s bigger than a straight ...

The angle in the following diagram is a reflex angle. The line turns through more than two right angles, but less than three right angles, so is between \(180^\circ\) and \(270^\circ\).