3 quarters clockwise is 270 degrees clockwise or 90 degrees anti(counter)-clocwise
270 degrees
It is 1/4 of a turn
The answer will depend on whether the rotation is clockwise or counterclockwise.
270
Rotation of 270 degrees clockwise or 90 degrees counter clockwise
270 rule represent a 270 rotation to the left which is very easy
There are 270 degrees in 3/4 of a rotation
It is multiplication by the 2x2 matrix 0 1-1 0
A measure of rotation MUST state whether it is clockwise or anti-clockwise. Unless the rotation is 0 degrees (ie no rotation) or 180 degrees (the two are the same). It must also specify the centre of rotation. Since you have not bothered to share these crucial bits of information, I cannot provide a more useful answer.
180 degrees in the plane perpendicular to the xy plane. In general, no rotation in the (x, y) plane will take it to (-x, y) unless x = y (or -y) and, in that case it is a 270 degree clockwise rotation.
1 rotation = 360 degrees 3/4 rotation = 270 degrees
3 quarters clockwise is 270 degrees clockwise or 90 degrees anti(counter)-clocwise
270 degrees
Both will end up on the same place. Using a compass rose as an example: 270 clockwise will point to the west. 90 counterclockwise will also point west.
Because 180 degrees clockwise is the same as 180 degrees counterclockwise.
The answer will depend on whether the rotation is clockwise or anti-clockwise.