At 280°, this is a reflex angle, which goes more than halfway around a circle. It is the "outside" of an 80° angle: together they make a full 360° circle.
280° is 7/9 of a full circle, or 14π/9 radians. If you face north and turn 280° clockwise, you end up facing between W and WNW (closest to west (W)).
280° angle facts
| Angle type | Reflex angle (between 180° and 360°) |
|---|---|
| Explement (adds to 360°) | 80° |
| Radians | 14π/9 ≈ 4.886922 |
| Gradians | 311.1111 grad |
| Fraction of a turn | 7/9 (77.78%) |
| Degrees, minutes, seconds | 280° 0′ 0″ |
| Compass bearing | between W and WNW (closest to west (W)) |
Trigonometric values of 280°
| Function | Value |
|---|---|
| sin 280° | −0.984808 |
| cos 280° | 0.173648 |
| tan 280° | −5.671282 |
280° on a protractor
How to draw a 280° angle with a protractor
- Subtract from 360°: 360° − 280° = 80°. A standard protractor only goes to 180°, so you draw the smaller angle first.
- Draw a straight line with a ruler and mark the vertex at one end.
- Place the protractor's center mark on the vertex, line up the 0° baseline with your line, and make a dot at 80°.
- Join the vertex to the dot. The inside angle is 80°; the outside angle, going the long way around, is 280°. Draw the angle arc on the outside and label it 280°.
- With a 360° protractor you can skip the subtraction: put 0° on your first line and mark 280° directly.
Drawing it a 280° angle without a protractor (rise and run method)
- Draw a straight baseline and measure 1.76 inches (about 1 3/4″) along it from the vertex.
- At that mark, draw a line straight up at 90° and measure exactly 10 inches up it.
- Join the top mark to the vertex. The angle at the vertex is 80°, because tan 80° ≈ 5.6713.
- That gives you 80°. The outside (reflex) angle is 280°.
Where you see 280° angles
- The Earth turns 280° on its axis in about 18 h 40 min.
- A 280° reflex angle is what you measure when you go the "long way" around, like the outside corner of a building or a turn of more than half a circle.
Related angles
280° angle FAQ
What type of angle is 280°?
A 280° angle is a reflex angle, because it is between 180° and 360°.
Does a 280° angle have a complement or supplement?
No. Complements add up to 90° and supplements to 180°, and 280° is already larger than both. What it does have is an explement (conjugate) of 80°, the angle that completes a full 360° circle.
How many radians is 280 degrees?
280° = 14π/9 radians ≈ 4.8869 rad. To convert degrees to radians, multiply by π/180: 280 × π/180 = 14π/9.
How do I measure a 280° angle on my screen?
Open the online protractor with 280° preset, or type 280 into its "Type an angle" box. You can then drag the arms onto your own lines to compare.
