Question

if line ab is parallel to line CD,and line CD is perpendicular to line EF.what can you conlude about AB andEF

Answer 1

If line AB is parallel to line CD, and line CD is perpendicular to line EF, AB is perpendicular to line EF due to the perpendicular transversal theorem,which says, if a line is perpendicular to another line, then it is perpendicular to the line parallel to the second line.

This theorem can be proved through the transversal postulate and theorems.