Question

Quadrilateral ABCD is rotated 90 degrees about the orgin. What are the coordinates of the quadrilateral A'B'C'D?

Answer 1

The coordinates of the object image are;

A {5,5}

B{5,1}

C{2,1}

D{1,5}

The rule for rotation of a point {x,y} through 90 degrees about the orgin, is that the object coordinates {x,y} change to image coordinates { y,-x}. This means the coordinates shift positions and the y coordinate acquires a negative sign. So in this case;

A {5,5}------- A' { 5,-5}

B{5,1}----------B' {1,-5}

C{2,1} ---------C' {1,-2}

D{1,5} ---------D' { 5,-1}

Answer

A.