Nuffield Free-Standing Mathematics Activity Geometrical design © Nuffield Foundation 2011 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 http://www.decoramic.co.uk/ Think about What is special about…. parallel lines are always the same distance apart perpendicular lines meet at 90 Triangles have 3 sides and 3 angles sum of the angles = 180 Think about a right-angled triangle What is special about …. an obtuse-angled triangle an acute-angled triangle has one angle of 90 has one angle greater than 90 Think about Why is it not possible for a triangle to have more than one right angle? has three angles all less than 90 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. Think about What is each angle in an equilateral triangle? has 3 different sides and 3 different angles. 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 Quadrilaterals Think about … What is special about these quadrilaterals? Rectangle Square Opposite sides equal Opposite sides parallel All sides equal Opposite sides parallel All angles are 90⁰ All angles are 90⁰ Quadrilaterals Think about … What is special about these quadrilaterals? Parallelogram Opposite sides equal Opposite sides parallel Opposite angles equal Rhombus All sides equal Opposite sides parallel Opposite angles equal Quadrilaterals Think about What is special about these quadrilaterals? Trapezium Kite One pair of sides parallel Two pairs of equal sides One pair of equal angles 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? Key words regular parallel circle perpendicular triangles scalene acute-angled quadrilaterals parallelogram rectangle other polygons pentagon isosceles right-angled equilateral obtuse-angled trapezium square rhombus kite hexagon octagon 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.