Types of angles, step by step

Before a child measures an angle, they have to see it.

The question
acuterightobtuse

Is this angle acute, right, or obtuse?

Name this angle

75°vs90°
75<90
75°acute
  1. Do not judge it by how big it looks — a long pair of arms makes an angle look wider than it is, and the arms are not the angle. Compare it to a RIGHT ANGLE instead; that is the one you can picture exactly.
  2. 75 is less than 90.
  3. Smaller than a right angle is ACUTE. (A useful check: it fits inside the corner of a page.)

How it works.

  1. 01

    Do not judge it by how big it looks — a long pair of arms makes an angle look wider than it is, and the arms are not the angle. Compare it to a RIGHT ANGLE instead; that is the one you can picture exactly.

  2. 02

    75 is less than 90.

  3. 03

    Smaller than a right angle is ACUTE. (A useful check: it fits inside the corner of a page.)