To overcome the problems that blur images and don't provide the best resolution from Earth, astronomers have started using flexible mirrors that change shape many times each second. This technique is called:

Two rigid transformations are used to map δhjk to δlmn. the first is a translation of vertex h to vertex l. what is the second transformation? a reflection across the line containing hk a rotation about point h a reflection across the line containing hj a rotation about point k