2D shapes

Hello, and welcome to Myriora Maths! Triangles, squares, hexagons. Flat shapes are everywhere! Let's learn their names, by counting their sides and corners.

A flat shape made of straight sides is called a polygon. The straight lines are sides. The corners where they meet are called vertices. One corner is a vertex.

The name tells you how many sides. A triangle has three sides. A quadrilateral has four. A pentagon has five, a hexagon has six, and an octagon has eight.

Some quadrilaterals have special names. A square has four equal sides and four right angles. A rectangle has four right angles, with two long sides and two short sides.

A regular shape has all its sides the same length, and all its angles the same. A square is a regular quadrilateral. A stop sign is a regular octagon.

Let's try one together. A shape has five sides. What is it called? Say it out loud!

Five sides: it's a pentagon!

Here's a question that catches lots of people. Is this shape a square? It's turned on its corner, so some people call it a diamond, and say it isn't a square. But turning a shape doesn't change it. It still has four equal sides and four right angles. It's a square!

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

Time's up! A hexagon has six sides, like the cells in a honeycomb!

Quick review. A polygon has straight sides and corners called vertices. Triangle three, quadrilateral four, pentagon five, hexagon six, octagon eight. A regular shape has equal sides and equal angles. And turning a shape doesn't change what it is. See you next time!