Given coordinates of the transformed image:
A'(6, 3),
B'(–2, 1), and
C'(1, 7).
We need to find the coordinates of the pre-image A, B and C.
The rule for rotation of 90° about the origin is (x,y) ---> (-y,x).
But we need to find the coordinates of the vertices of the pre-image.
<em>So, we need to apply rule (-y,x) ---->(x,y).</em>
Applying rule,
A'(6, 3) -----> A (3, -6)
B'(–2, 1) -----> B(1, 2)
C'(1,7) -----> C (7, -1).
<h3>Therefore, coordinates of the vertices of the pre-image are </h3><h3>A (3, -6)</h3><h3>B(1, 2)</h3><h3>C (7, -1).</h3>