Question

What set of reflections would carry triangle abc onto itself?

Answer 1

Since all reflections are inverse of itself, carrying any reflection about the same axis twice will carry the preimage back to itself.

Answer 2

Answer is y axis , x axis, y axis , x axis .

Let The triangle ABC is in first quadrant of a two dimensional graph where it is reflected by positive of y axis and it is reflected image will be in second quadrant ,there it is reflected by negative of x axis and the reflected image will be in third quadrant now, here it is reflected by negative of y axis and its reflected image will be in fourth quadrant ,finally it will reflected by positive of x axis and its reflected image will be back in first quadrant.

So the answer is y axis , x axis, y axis , x axis are the of reflections which would carry triangle onto itself.