Chapter 1: Shapes Around Us

Open your eyes and look around , your tiffin box, the chapati on your plate, the kite in the sky. Everything has a shape! Let us go on a shape hunt.

What we'll learn

• Names of flat shapes like triangle, square, rectangle and circle.
• Names of solid shapes like cube, cuboid, cylinder, cone and sphere.
• How to count sides and corners of a flat shape.
• How to count faces, edges and vertices of a solid.
• How shapes fit together without leaving gaps.

The big idea

Shapes are everywhere. A flat shape, like the face of a coin, you can draw on paper. We call these 2D shapes , they have only length and width. A solid shape, like a ball, you can hold in your hand. These are 3D shapes , they also have height or thickness.

A triangle has 3 sides and 3 corners. A square has 4 equal sides and 4 corners. A rectangle has 4 sides but two are longer. A circle has no corners at all , it is a smooth curve.

Now the solids. A brick is a cuboid. A dice is a cube. A football is a sphere. An ice-cream cone is a cone. A pencil and a tin of biscuits are like cylinders.

Each solid has flat parts called faces, sharp edges where two faces meet, and pointy corners called vertices. A cube has 6 faces, 12 edges and 8 vertices. Try counting them on a dice!

Shapes can also fit together. Floor tiles are usually square or rectangle because they cover the floor with no gaps. This is called tiling.

Explore with examples

1. How many corners does a stop sign have?

A stop sign is an octagon. Count the sides: 1, 2, 3, 4, 5, 6, 7, 8. So it has 8 sides and 8 corners.

2. Riya has a Rubik's cube. How many small faces are showing on the outside?

A Rubik's cube is a cube, so it has 6 big faces. Each big face is made of 9 small squares. Total small faces = 6 × 9 = 54.

3. Sort these objects: laddoo, brick, samosa, glass.

• Laddoo → sphere
• Brick → cuboid
• Samosa → like a triangular pyramid (tetrahedron)
• Glass → cylinder

4. Can you tile a floor using only circles?

No. Circles will always leave little gaps between them. That is why floors use squares, rectangles or hexagons.

Hands-on activities

Shape Hunt at Home

Walk through your house with a notebook. Note down 10 things and write the shape of each. Is the door a rectangle? Is the wheel of a toy car a circle?

Dice Detective

Pick up any dice. Count its faces, then its edges, then its corners. Now try a matchbox. Note both numbers down. Do they match?

Paper Folding Squares

Take a rectangular sheet of paper. Fold one corner so the short side lies on the long side. The folded part is a square! Cut along the extra strip and you have a perfect square.

Try it yourself

1. How many sides does a hexagon have?
2. Name 3 things in your kitchen that are cylinders.
3. A cuboid has how many edges?
4. Draw any shape with 5 sides. What is it called?
5. Which has more corners: a triangle or a square?
6. Can two triangles together make a rectangle? Try drawing it.
7. Look at a chapati and a roti box. Which is 2D and which is 3D?

Recap

• 2D shapes are flat; 3D shapes are solid.
• Triangles have 3 sides, quadrilaterals have 4, pentagons have 5, hexagons have 6.
• Solids have faces, edges and vertices.
• Some shapes tile perfectly, others leave gaps.