Question

On a coordinate plane, 2 triangles are shown. The first triangle has points A (negative 2, 1), C (negative 4, 1), and B (negative 3, 4). The second triangle has points A prime (1, negative 2), B prime (4, negative 3), and C prime (1, negative 4).
What is the rule for the reflection?

ry=x(x, y) → (–y, –x)
ry=–x(x, y) → (–y, –x)
ry=x(x, y) → (y, x)
ry=–x(x, y) → (y, x)

Answer 1

Reflection across the line y = x.

Rule: r_{y=x}(x,y) → (y,x).

Check: (-2,1) → (1,-2), (-3,4) → (4,-3), (-4,1) → (1,-4), which match the given A', B', C'.