An acute angle* measures less than 90^. It looks like a sharp corner.

Here are the types of angles, building on the previous explanation: An acute angle* measures less than 90^. It looks like a sharp corner. A right angle* measures exactly 90^. It forms a perfect square corner, often indicated by a small square symbol at the vertex. An obtuse angle* measures greater than 90^ but less than 180^. It looks wider than a right angle but not flat. A straight angle* measures exactly 180^. It forms a straight line. A reflex angle* measures greater than 180^ but less than 360^. It's the "outside" angle when two rays meet, encompassing more than a straight line.