Grade 3 · Unit 6: Shape

2D shapes and their properties

Sides, angles and parallel lines.

Shapes in kites

Kites in Old Dhaka come in many shapes. Many are quadrilaterals – 4-sided shapes. We can describe shapes by their properties.

Quadrilaterals

All have 4 sides. A square and a rectangle have 4 right angles. A parallelogram has 2 pairs of parallel sides.

Triangles

An equilateral triangle has 3 equal sides. A right-angled triangle has a square corner. An isosceles triangle has 2 equal sides.

Regular or irregular?

A regular shape has all sides and angles equal. An irregular hexagon still has 6 sides, but they are not all equal. A square is a regular quadrilateral.

Polygon or not?

A polygon is a closed shape with straight sides only. A circle and a semicircle are not polygons – they have curves. Join two shapes to make a new one: two squares make a rectangle.

Same shape, same size

Congruent shapes are exactly the same shape and size. Similar shapes are the same shape, but bigger or smaller. All squares are similar to each other.

What I learnt

• I can name quadrilaterals and triangles.
• I can find right angles and parallel sides.
• I know what “regular” means.