Mathematics for IGCSE & O level - Transformations (Section 2 - No. 22)
If a triangle has vertices A(1, 1), B(1, 3), and C(3, 1), what are the vertices of the image after a reflection in the line y=x?
A'(1, 1), B'(3, 1), C'(1, 3)
A'(-1, -1), B'(-1, -3), C'(-3, -1)
A'(1, -1), B'(1, -3), C'(3, -1)
A'(3, 1), B'(3, 3), C'(1, 1)
คำอธิบาย
Reflection over y=x swaps x and y coordinates.