Angle — 15° (Acute Angle) — free printable diagram

What is a 15 degree angle?

A 15 degree angle (15°) is an acute angle — it measures less than 90°, so the opening is narrower than a square corner. This diagram shows 15° opened between two arms meeting at a vertex.

Measure

15°

Type of angle

Acute angle

Complement (adds to 90°)

75°

Supplement (adds to 180°)

165°

Reflex angle on the other side

345°

In radians

π/12 (≈0.262)

Fraction of a full turn

1/24 of a turn

• A 15° angle is an acute angle because it measures less than 90°, so the opening is narrower than a square corner.
• Angles on a straight line add up to 180°, so the angle next to this one measures 180° − 15° = 165°.
• Two angles that add up to 90° are complementary, so the complement of 15° is 90° − 15° = 75°.
• Angles round a point add up to 360°, so the reflex angle on the other side of these arms measures 360° − 15° = 345°.
• To measure or draw it, put the centre of the protractor on the vertex where the two arms meet, line one arm up with the 0° mark, and read the scale that starts at 0° on that arm until you reach 15°.
• In radians, 15° × π/180 = π/12, which is about 0.262.