A reflection is a type of transformation in which a figure flips over a line, known as the line of reflection. In a reflection, the image is congruent to the pre-image. Therefore, a reflection is an isometry. You will investigate reflections of geometric figures on the coordinate plane. As you progress through this topic, make sure to have plenty of graph paper to help you practice.

Essential Questions

• How do you reflect a geometric figure on the coordinate plane?
• How can you determine the line of reflection of a geometric figure on the coordinate plane?

 

Warm-Up

Pretend for a moment that you are encountering an extraterrestrial being who has no idea what a mirror is. This alien creature asks you, "What is the purpose of a mirror?" What would you say? Continue through this topic to dig deeper into the concept of reflection in regard to geometric figures on the coordinate plane.