South. 90 degrees is 1/4 of a complete rotation, which is 360 degrees.
http://www.mathsisfun.com/geometry/degrees.html
North East
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South
Unfortunately there is no consistent direction: it depends on the context. If dealing with bearings (eg navigation) North is 000 degrees and the angle is measured in the clockwise direction starting from the Northward direction. In the context of coordinate geometry, particularly if working with polar coordinates, angles are measured in the anti-clockwise direction, starting with the x-axis (pointing East) as 0 degrees. Generally speaking, though, angles may be measured in any direction.
If you turn 225 degrees anticlockwise you are now facing northeast
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North East
sue me en
South
West
As long as you are not standing on either the North or South Poles, the east would be to your right.
East-facing azimuth = 90°Northwest-facing azimuth = 315°To turn from east-facing to northwest facing, you turn 225° to the right (clockwise).
Use a compass to identify which direction is north. Face that direction, then turn ninety degrees to your right. You are facing east.
Southeast
For sailors, bearing is the angle measured clockwise from North. For mathematicians, direction is measured counter-clockwise from the positive x-axis. Thus, due East as a bearing would be 90 degrees, since it is 90 degrees clockwise from North, and East as a direction would be 0 degrees, since East is the same as the positive x-axis. So yeah, there you go.
"East" is a directional term that refers to the direction you would face when observing the sun rise. It can also be found by rotating 90 degrees clockwise from north, or by rotating 90 degrees counterclockwise from south.
90 degrees from North would be East, then another 45 degrees from that would bring it halfway to South. Therefore, 135 degrees clockwise from North is Southeast.