Question

the figure shows four congruent isosceles right triangles on a coordinate plane. which triangle is the image of △1 reflected over the line y = -x? triangle number

Explanation:

Step1: Recall reflection rule

The rule for reflecting a point $(x,y)$ over the line $y = -x$ is $(-y,-x)$. Triangle 1 is in the second - quadrant.

Step2: Analyze position of reflected triangle

When we reflect a point in the second - quadrant over the line $y=-x$, the resulting point will be in the fourth - quadrant. Among the given triangles, triangle 3 is in the fourth - quadrant.

Answer:

3