Question

the coordinates of the vertices of triangle QRS are shown
Q (2,3)
R (-2,1)
S (-2,5)

the triangle is rotated 90 degrees clockwise about the origin to create triangle Q'R'S'

What are the coordinates of R'?

Answer 1

A 90° clockwise rotation about the origin sends (x,y) to (y, −x).
For R(−2,1): R' = (1, −(−2)) = (1, 2).