Parallel and perpendicular

Hello, and welcome to Myriora Maths! Railway tracks never meet. And the corner of a page is a perfect right angle. These are parallel and perpendicular lines. Let's meet them.

Parallel lines always stay the same distance apart. They never meet, however long you make them. We mark them with little matching arrows.

Perpendicular lines meet at a right angle, ninety degrees. We mark the corner with a small square.

Look around a room. The opposite edges of a door are parallel. The edge of the floor and the edge of a wall are perpendicular.

Shapes can have them too. A rectangle has two pairs of parallel sides, and four right angles. A parallelogram has two pairs of parallel sides, but no right angles.

Let's try one together. In the letter H, are the two upright lines parallel or perpendicular? Say it out loud!

They stay the same distance apart and never meet. They're parallel! And the middle line is perpendicular to both.

Here's a question that catches lots of people. Are these two lines perpendicular? They cross, so some people say yes. But they cross at a slant, not at a right angle. Perpendicular lines must meet at exactly ninety degrees.

Your turn! How many pairs of parallel sides does a square have? Pick the right card. You've got twenty seconds, or pause the video. Go!

Time's up! The top and bottom are parallel, and so are the two sides. That's two pairs!

Quick review. Parallel lines stay the same distance apart and never meet: we mark them with arrows. Perpendicular lines meet at a right angle: we mark them with a small square. Lines that just cross aren't always perpendicular. See you next time!