In rotation of clockwise movement maps (x , y) (y,-x)

The correct answer is: 90°

Given Data:
The point (x, y) is transformed to (x , y) (y,-x) in clockwise direction.
>>> we were asked to find the Angle of Rotation.
>>>The coordinates of a point (x, y) after rotation through 90 degrees in clockwise direction are:
(x', y') = (x cos - y sin , y cos + x sin)
>>>we were given that (x', y') = (y, -x)
>>> (y, -x) = (x cos - y sin , y cos + x sin)
Hence, y = x cos - y sin and -x = y cos + x sin
By solving the above equation's we get:
(x  y)  = x²cos - (x  y) sin
and        (y  -x) = y²cos + (x  y) sin

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0 = (x²+y²)cos
*This implies cos=0, then:
 = 90 degrees.
>>>Therefore, the angle of rotation is 90 degrees.

* In Mathematics, rotation means the Circular movement of an object around one fixed point.

* In rotation, the image after transformation remains constant.

* Hence, it is called as a rigid transformation.

* No Change in shape and size.

* The Shape rotates counter- clockwise when the degrees is positive and rotates clockwise when degrees is negative.

*The Rotation of a point (x, y) about origin and through angle alpha, then:
New coordinates of a point (x, y) after it's rotation becomes (x cos - y sin , y cos + x sin).