What is the image of triangle 𝐹𝐷𝐿 under reflection in line 𝐸𝐹?
Let’s start this question by finding triangle 𝐹𝐷𝐿, which is marked here in orange on our diagram. Next, our line 𝐸𝐹, which we can mark in pink on our diagram. To find the image then, we need to see what shape will be created by this line of reflection.
The point 𝐷 would be reflected to give us point 𝐶. Our point 𝐹 lies on the line of reflection, so it will be its own image. And the same will be true of point 𝐿. The image that will be created will have the same shape as triangle 𝐹𝐷𝐿. Therefore, the image of triangle 𝐹𝐷𝐿 under reflection in line 𝐸𝐹 is triangle 𝐹𝐶𝐿.