A 318° angle is a reflex angle: it is bigger than a straight line (180°) but less than a full turn (360°). It is the "outside" of a 42° angle: together they make a full 360° circle.
318° is 53/60 of a full circle, or 53π/30 radians. The minute hand of a clock sweeps 318° in 53 minutes. If you face north and turn 318° clockwise, you end up facing between NW and NNW (closest to northwest (NW)).
318° angle facts
| Angle type | Reflex angle (between 180° and 360°) |
|---|---|
| Explement (adds to 360°) | 42° |
| Radians | 53π/30 ≈ 5.550147 |
| Gradians | 353.3333 grad |
| Fraction of a turn | 53/60 (88.33%) |
| Degrees, minutes, seconds | 318° 0′ 0″ |
| Compass bearing | between NW and NNW (closest to northwest (NW)) |
Trigonometric values of 318°
| Function | Value |
|---|---|
| sin 318° | −0.669131 |
| cos 318° | 0.743145 |
| tan 318° | −0.900404 |
318° on a protractor
How to draw a 318° angle with a protractor
- Subtract from 360°: 360° − 318° = 42°. 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 42°.
- Join the vertex to the dot. The inside angle is 42°; the outside angle, going the long way around, is 318°. Draw the angle arc on the outside and label it 318°.
- With a 360° protractor you can skip the subtraction: put 0° on your first line and mark 318° directly.
Drawing it a 318° angle without a protractor (rise and run method)
- Draw a straight baseline and measure exactly 10 inches along it from the vertex.
- At the 10-inch mark, draw a short line straight up at 90° (use a carpenter's square or the corner of a sheet of paper).
- Measure 9 inches (about 9″) up that line and make a mark.
- Join the mark to the vertex. The angle at the vertex is 42°, because tan 42° ≈ 0.9004.
- That gives you 42°. The outside (reflex) angle is 318°.
Where you see 318° angles
- The Earth turns 318° on its axis in about 21 h 12 min.
- A 318° 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
318° angle FAQ
What type of angle is 318°?
A 318° angle is a reflex angle, because it is between 180° and 360°.
Does a 318° angle have a complement or supplement?
No. Complements add up to 90° and supplements to 180°, and 318° is already larger than both. What it does have is an explement (conjugate) of 42°, the angle that completes a full 360° circle.
How many radians is 318 degrees?
318° = 53π/30 radians ≈ 5.5501 rad. To convert degrees to radians, multiply by π/180: 318 × π/180 = 53π/30.
How do I measure a 318° angle on my screen?
Open the online protractor with 318° preset, or type 318 into its "Type an angle" box. You can then drag the arms onto your own lines to compare.
