3rd Grade Parallel and Perpendicular Lines Worksheet: 6 Line Pairs

Two lines on a page can cross, meet at a square corner or never meet at all. This 3rd grade parallel and perpendicular lines worksheet turns those three cases into six short tasks. Each task shows one pair of coloured lines with arrows at both ends, and it then asks one question, such as "Check whether these lines are perpendicular." Your child answers yes or no and writes a short reason, which is the real heart of the page. Two tasks ask about intersecting lines, two about perpendicular lines and two about parallel lines. The page sits on light grid paper, so the angles are easy to see. Page two is the answer key, with a full sentence under each pair.

Six answers to check

The answers are no for 1, no for 2 and yes for 3, and then yes for 4, yes for 5 and no for 6. All six answers in the key are right, and each one comes with a reason.

However, the key has a few small slips. In item 6, it says "there are not parallel" instead of "they are not parallel." In item 2, it says the lines "do not meet to form a right angle," but in fact the lines do meet, just not at a right angle. Item 4 also has a double space. Note that US schools often teach these words in grade 4, so this page is a stretch.

At the table: test for perpendicular lines with a corner

Give your child a sheet of paper and show them its square corner, which is a right angle. To test a pair of crossing lines, they place the corner where the lines meet, and if both edges sit on the lines, the lines are perpendicular. Otherwise, they only intersect.

For parallel lines, use a different test. Your child measures the gap between the lines at two places with a ruler. If the gap stays the same, the lines are parallel, because they will never meet.

After the page: a line hunt at home

First, look for line pairs around the house, such as the rails of a ladder, the edges of a door or the strings of a tennis racket. Your child names each pair as parallel, perpendicular or just intersecting. Then they use the paper corner to check any square corner they find. Finally, this hunt shows that the three words describe real objects, not only drawings.