2-D shapes (age 6+)
Identify and describe properties of 2-D shapes including the number of sides and line symmetry in a vertical line
What a learner can do afterwards
- Count the number of sides of a given 2-D shape
- Identify whether a 2-D shape has a vertical line of symmetry
- Use properties (number of sides, symmetry) to describe and distinguish between shapes
1 · Read
A 2-D shape is flat, like a shape you draw on paper. Every 2-D shape has sides, the straight or curved edges that make its outline. To count the sides, touch each edge once and say the number.
Priya looks at a hexagon. She touches each edge and counts: 1, 2, 3, 4, 5, 6. The hexagon has 6 sides.
Some shapes have a vertical line of symmetry. Imagine a straight line going up and down through the middle of the shape. If both halves match exactly, like a mirror, the shape has a vertical line of symmetry.
A square and a rectangle both have 4 sides and a vertical line of symmetry, but a scalene triangle, with three different side lengths, does not have one. Counting sides and checking for symmetry helps you tell shapes apart.
Count each side once, and check if a straight up-and-down line splits the shape into two matching halves.
More to read
Geometry: FAQ
Shapes are sorted by their parts: sides, corners, and faces. Flat shapes like triangles and squares live on paper, while solid shapes like cubes and balls fill space. Counting parts is the fastest way to name a mystery shape. Every face of a solid is itself a flat shape. Learn the faces and the solid gives itself away.
Polygons review
Polygons are flat closed shapes made of straight sides. Triangles have three sides, quadrilaterals have four, and pentagons have five. Count the sides and corners to crack the name. Round shapes with curves are not polygons at all. A vertical fold that matches proves a mirror line.
4.1: Polygons
Polygons are named by their side counts, and every side meets its neighbors at corners. Drawing them on dot paper trains your eye for straight edges and closed loops. Compare side lengths and corner squareness to tell cousins like squares and rectangles apart. Symmetry folds give extra clues about a shape family.
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2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.