1. Nuffield Free-Standing Mathematics Activity
Geometrical design

2. Geometrical design
Can you name any of the geometrical shapes in these pictures?
This activity is about recognising shapes and their properties
Left-hand photo Decoramic Tile Centre

3. Think about What is special about….
parallel lines
are always the same distance apart
perpendicular lines
meet at 90

4. Triangles Think about What is special about ….
have 3 sides and 3 angles
sum of the angles = 180
Think about What is special about ….
a right-angled triangle
an obtuse-angled triangle
an acute-angled triangle
has one angle of 90
has one angle greater than 90
has three angles all less than 90
Think about Why is it not possible for a triangle to have more than one right angle?

5. Triangles Think about What is special about….
an equilateral triangle
an isosceles triangle
a scalene triangle
has 3 equal sides and 3 equal angles.
has 2 equal sides and 2 equal angles.
has 3 different sides and 3 different angles.
Think about What is each angle in an equilateral triangle?

6. Polygons Think about the names of these polygons….
A quadrilateral has 4 sides.
Sum of the angles = 360
A pentagon has 5 sides.
A hexagon has 6 sides.
An octagon has 8 sides

7. Quadrilaterals
Think about … What is special about these quadrilaterals?
Opposite sides equal
All sides equal
Opposite sides parallel
Opposite sides parallel
Rectangle
All angles are 90⁰
Square
All angles are 90⁰

8. Quadrilaterals
Think about … What is special about these quadrilaterals?
Rhombus
Opposite angles equal
Opposite sides parallel
Opposite sides equal
Parallelogram
Opposite angles equal
Opposite sides parallel
All sides equal

9. Quadrilaterals Think about What is special about these quadrilaterals?
Kite
Trapezium
Two pairs of equal sides
One pair of sides parallel
One pair of equal angles

10. Regular polygons Think about … What does ‘regular’ mean?
Think about What is another name for a regular triangle? What is another name for a regular quadrilateral?

12. Key words regular parallel perpendicular circle
triangles scalene isosceles equilateral acute-angled right-angled obtuse-angled
quadrilaterals
parallelogram trapezium rhombus
rectangle square kite
other polygons
pentagon hexagon octagon

13. Geometrical design At the end of the activity
Name the different types of triangles.
Name each special type of quadrilateral. List their properties.
What does the term 'regular' mean? What is another name for a regular quadrilateral?
What types of jobs involve using geometrical shapes? List as many as you can.