Quadrilateral abcd is transformed according to the rule (x, y) → (y, –x). which is another way to state the transformation?
r0, 90°
r0, 180°
r0, 270°
r0, 360°

The answer
there is no more explanation about this question, the solution can be found easily by applying the rule of transformation of rotation

for example, the properties of rotation transformation are:
A rotation preserves length but does not necessarily preserveslope of a line.
A 90° rotation ( 1/4 turn) anticlockwise about the origin changesthe point (x; y) to (-y; x).
A 180° rotation ( 1/2 turn) clockwise or anticlockwise about theorigin changes the point (x; y) to (-x;-y).
A 270° rotation ( 3/4 turn) anticlockwise changes about the originthe point (x; y) to (y;-x).
 so the answer is 
R0, 270°

5\16 x 2\5 = 10/80simplify to 1/80