Three-dimensional shapes
3D shapes are solid shapes we can hold. Some can roll and some can stack.
Key idea / 要点
A cube has 6 square faces (like a dice). A cuboid is like a box. A cylinder is like a can. A cone has a point. A sphere is a ball.
Roll or stack?
Round shapes like the sphere and cylinder can roll, because they have curved sides. Flat-faced shapes like the cube and cuboid can stack neatly on top of each other. A cone can roll around its curved side but not stand and roll like a ball.
Worked example / 例题
Which shape is like a tin of milk?
A tin is round with two flat circle ends. It is a cylinder.
Remember / 记住
- A cube has 6 equal square faces.
- A sphere is round and can roll.
- A cone has one flat face and a point.
- Look for 3D shapes around you, like balls, boxes, and cans.