Angles in parallel lines worksheets

A line crossing two parallel lines makes eight angles, and only a few of them are different. These free printable worksheets ask which pair the marked angles are.

Angles in parallel lines
Angles in parallel lines worksheet — Angles in fives, 40° and up, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

Two of the three facts here give an answer that is already printed on the figure. Corresponding angles are equal and alternate angles are equal, so x is the number the child was given. That looks like a question with nothing in it and is the opposite: a child who cannot see which pair it is has no way to produce that number, and a child who can is finished. Reading the picture is the whole of this standard.

Why this sheet works

Co-interior angles are the exception and belong on every mixed sheet for that reason. They are the one pair that is not equal — they add to 180° — so a sheet of only the first two teaches "find the matching angle and copy it", which fails on the first co-interior pair a test prints.