2D shapes
Polygons and quadrilaterals and their properties. Read one part at a time and tap “I know this”. Then test yourself in the quiz.
Know it already? Jump straight to the quiz
Polygons
A polygon is a flat shape with straight sides. A circle is not a polygon (curved edge).
| Shape | Sides |
|---|---|
| triangle | 3 |
| quadrilateral | 4 |
| pentagon | 5 |
| hexagon | 6 |
| heptagon | 7 |
| octagon | 8 |
A regular polygon has equal sides and equal angles.
A shape is named by its number of sides, not by how neat it looks: any shape with 5 straight sides is a pentagon. If all the sides and angles are equal it is a regular pentagon; if not, it is an irregular pentagon.
Quadrilaterals
| Quadrilateral | Properties |
|---|---|
| square | 4 equal sides, 4 right angles |
| rectangle | opposite sides equal, 4 right angles |
| parallelogram | opposite sides equal and parallel |
| rhombus | 4 equal sides, opposite sides parallel (a square is a special rhombus with 4 right angles) |
| trapezium | one pair of parallel sides |
| kite | two pairs of adjacent equal sides |
Angles in shapes
- A right angle is a square corner, like the corner of a page. We mark it with a small square.
- An angle smaller than a right angle is sharper (narrower) than a square corner: an acute angle.
- An angle bigger than a right angle is wider (more open) than a square corner: an obtuse angle.
- A square and a rectangle each have 4 right angles.
Test an angle with the corner of a sheet of paper: if it fits exactly, it is a right angle.
Remember this and test yourself
- A polygon has straight sides.
- Pentagon 5, hexagon 6, heptagon 7, octagon 8 sides.
- A square is a special rectangle.
- Trapezium: one pair of parallel sides.
- A right angle is a square corner, like the corner of a page.
Write these points in your book. Read them again the night before the test.
A hexagon like a honeycomb cell; an octagon like a stop sign.
Important words
First say the answer yourself, then turn the card over.
Match column A to column B
Tap a word in column A, then its meaning in column B. You can also start in column B.
True or false?
Read the question and the answer. Is the answer right? Tap True or False.
Now the real quiz!
The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.
Take the quiz: 2D shapes- Let your child work the examples on paper and explain them to you.
- The ticks (“I know this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 5 Mathematics. Always check your teacher’s notes and textbook too.