Geometrical Shapes Important Notes - Class 5 Math Olympiad | Complete Learning Material PDF

Geometrical shapes are the basic figures studied in geometry. They are all around us-in books, toys, buildings and nature. Knowing the names and simple properties of shapes helps us to recognise patterns, solve problems and make drawings.

Shapes come in two main kinds by their dimensions: two-dimensional (2D) shapes and three-dimensional (3D) shapes. A 2D shape lies flat on a surface. A 3D shape takes up space. Let's explore both types of shapes.

2D Geometrical Shapes

Many 2D shapes are flat figures made of straight or curved lines. Useful words to know:

• Side - a straight line that forms part of a 2D shape.
• Vertex (plural: vertices) - the point where two sides meet.
• Angle - the amount of turn between two sides.
• Perimeter - the distance all around a 2D shape.

Circle

A circle is a perfectly round 2D shape. Every point on the edge of a circle is the same distance from a central point called the centre. 
Examples: a coin, a bicycle wheel, a round plate or a pizza base.

Square

A square has four straight sides that are all equal in length. Every corner of a square is a right angle (90°). A square has four vertices and four sides. 
Examples: some pieces of chocolate, a sticky note, a small tile.

Triangle

A triangle is a 2D shape with three sides and three vertices. 
Examples: a slice of pizza, a roof gable, triangular road signs.

Rectangle

A rectangle has four sides and four right angles. Opposite sides are equal in length. A square is a special rectangle where all four sides are equal.
Examples: a book cover, a school notebook, a TV screen.

Oval

An oval looks like a stretched circle. It has no corners or straight sides. An egg is a familiar example of an oval shape.
Examples: an egg, some mirrors, certain sports tracks.

3D Geometrical Shapes

Three-dimensional (3D) shapes have depth and can be touched. Useful words to know:

• Face - a flat or curved surface of a 3D shape.
• Edge - a line where two faces meet.
• Vertex (corner) - a point where edges meet.
• Surface - the outside part of a 3D shape.

Sphere

A sphere is the 3D circle: every point on its surface is the same distance from the centre. A sphere has no edges and no vertices.
Examples: a soap bubble, a ball (like a cricket ball or tennis ball).

Cube

A cube has six square faces, all faces equal in size. A cube has 12 edges and 8 vertices. Each face is a square and all the angles between faces are right angles.
Examples: a small gift box, dice, certain building blocks.

Cylinder

A cylinder has two circular faces (called bases) connected by one curved surface. A cylinder has no vertices. It has two circular edges where the curved surface meets the bases.
Examples: a can of food, a water glass, a roll of stickers.

Cone

 A shape with a circular base and a pointed top.
Examples: an ice-cream cone, a traffic cone.

Pyramid

A pyramid has a flat base and triangular faces that meet at a single vertex. The number of triangular faces equals the number of sides of the base. A common example is a square pyramid with a square base and four triangular faces.

Examples: the Egyptian pyramids (square pyramid), tent shapes, some roof designs.

Let's Do A Fun Activity!

• Look around your classroom or home and name five 2D shapes and five 3D shapes you can see. Draw each one and label its sides, faces, vertices or centre as appropriate.
• Take a sheet of paper and cut out shapes: circle, square, rectangle, triangle and oval.
• Count and write the number of sides and vertices for polygons you find. For 3D objects, list faces, edges and vertices where possible.