Question

a glide reflection is a composition of a followed by as shown earlier, each of these can be expressed as a composition of reflections. it follows that their composition, a glide reflection, can also be expressed as a composition of reflections. each type of rigid motion has now been considered, so the proof is complete.

Explanation:

A glide reflection is a well - defined transformation in geometry. By the properties of geometric transformations, a glide reflection is composed of a translation (a type of rigid motion that slides a figure) followed by a reflection (a rigid motion that flips a figure over a line). Since both translation and reflection can be expressed as compositions of reflections (translation can be thought of as a composition of two parallel reflections and reflection is itself a single reflection operation in the context of composition of reflections for rigid motions), their composition (glide reflection) can also be expressed as a composition of reflections.

Answer:

A glide reflection is a composition of a translation followed by a reflection.