Angle types: acute, right, obtuse, straight, reflex

Angle “type” is a quick label based on the size of the angle. In the tool, the mode you choose (180° vs 360°) affects whether you can measure reflex angles correctly.

Common angle types

Acute (0°–90°)
Smaller than a right angle. Many photo/diagram angles fall here once aligned.
Right (90°)
A perfect corner. Use Snap if you want to land on exactly 90°.
Obtuse (90°–180°)
Wider than a right angle but less than a straight line.
Straight (180°)
A flat line. Useful for checking alignment and baselines.
Reflex (180°–360°)
The “outside” angle that goes past 180°. Use 360° mode to read it correctly.

How this maps to the tool

  1. Use the grid/rotate/flip to align a clear edge first; misalignment is the #1 reason a type looks wrong.
  2. If you need an angle larger than 180°, switch to 360° mode before reading the value.
  3. Keep the protractor center on the vertex and align the baseline with one side, then rotate to match the other side.
  4. If the reading keeps jumping, adjust Snap (common angles vs step) or temporarily turn Snap off for a free move.

Related

Angle Types (Acute, Right, Obtuse, Straight, Reflex) | Smart Protractor