Acute angle

75 Degree Angle

5π/12 ≈ 1.308997 radians · 5/24 (20.83%) of a circle

Diagram of a 75 degree angle75°
Acute angle: 75°

Key facts

75°

Angle type
Acute angle
Complement (adds to 90°)
15°
Supplement (adds to 180°)
105°
Explement (adds to 360°)
285°
Open 75° in the online protractor

A 75° angle is an acute angle: it is smaller than a right angle (90°). It is more than half of a right angle. Add 15° more and you get a square corner.

75° is 5/24 of a full circle, or 5π/12 radians. If you face north and turn 75° clockwise, you end up facing between ENE and E (closest to east-northeast (ENE)).

75° angle facts

Angle type Acute angle (between 0° and 90°)
Complement (adds to 90°) 15°
Supplement (adds to 180°) 105°
Explement (adds to 360°) 285°
Radians 5π/12 ≈ 1.308997
Gradians 83.3333 grad
Fraction of a turn 5/24 (20.83%)
Degrees, minutes, seconds 75° 0′ 0″
Slope (grade) 373.21%
Roof pitch 44.78/12
Compass bearing between ENE and E (closest to east-northeast (ENE))

Trigonometric values of 75°

FunctionValue
sin 75° (√6 + √2)/4 ≈ 0.965926
cos 75° (√6 − √2)/4 ≈ 0.258819
tan 75° 2 + √3 ≈ 3.732051

75° on a protractor

Protractor showing 75 degrees0180101702016030150401405013060120701108010090901008011070120601305014040150301602017010180075°
On a 180° protractor, 75° is read on the scale that starts at 0° on the base arm. Try it in the interactive protractor →

How to draw a 75° angle with a protractor

  1. Draw a straight line with a ruler. This is the first arm; mark the vertex at one end.
  2. Place the center mark of the protractor exactly on the vertex and line up the 0° baseline with your line.
  3. Find 75° on the row of numbers that reads 0° on your line (protractors have two rows running in opposite directions) and make a small dot at the edge.
  4. Remove the protractor and draw a line from the vertex through the dot. Mark the angle with an arc and label it 75°.

Drawing it a 75° angle without a protractor (compass and ruler)

  1. Draw a 90° angle: construct a perpendicular line (draw arcs from two points on the line and join their crossing points).
  2. Inside it, starting from the second arm, mark a 15° angle: construct a 30° angle, then bisect it.
  3. What is left between the first arm and the new line is 90° − 15° = 75°.

Where you see 75° angles

  • The 4-to-1 ladder rule (1 foot out for every 4 feet up) sets a ladder at about 76°, near the 75.5° that ladder safety guidelines recommend.
  • 75° of latitude on Earth spans roughly 5,179 miles north to south.
  • The Earth turns 75° on its axis in about 5 hours.
  • Narrow acute angles like 75° show up in ramps, roof slopes, scissors blades, the tip of a pencil and the V of a flying flock of birds.

75° angle FAQ

What type of angle is 75°?

A 75° angle is an acute angle, because it is between 0° and 90°.

What are the complement and supplement of 75°?

The complement of 75° is 15° (together they make 90°), and the supplement is 105° (together they make 180°).

How many radians is 75 degrees?

75° = 5π/12 radians ≈ 1.309 rad. To convert degrees to radians, multiply by π/180: 75 × π/180 = 5π/12.

How do I measure a 75° angle on my screen?

Open the online protractor with 75° preset, or type 75 into its "Type an angle" box. You can then drag the arms onto your own lines to compare.