3 hours

Year 9 Support

Autumn Term

Unit 3

Geometrical reasoning: lines, angles and shapes

NNS P178-189

Autumn Term

Spring Term

Summer Term

Support (from Y7 teaching programme) • Identify parallel and perpendicular lines; know the sum of angles at a point, on a straight line and in a triangle, and recognise vertically opposite angles. • Use angle measure; distinguish between and estimate the size of acute, obtuse and reflex angles.
Core (from Y8 teaching programme) • Solve geometrical problems using side and angle properties of equilateral, isosceles and right-angled triangles and special quadrilaterals, explaining reasoning with diagrams and text • Identify alternate angles and corresponding angles; understand a proof that: – the sum of the angles of a triangle is 180º and of a quadrilateral is 360º; – the exterior angle of a triangle is equal to the sum of the two interior opposite angles. • Classify quadrilaterals by their geometric properties
Extension (from Y9 teaching programme) • Explain how to find, calculate and use (a) the sums of the interior and exterior angles of quadrilaterals, pentagons and hexagons (b) the interior and exterior angles of regular polygons • Solve problems using properties of angles, of parallel and intersecting lines, and of triangles and other polygons
Starters	Main	ICT	Scaffolding	Key Questions	Notes
1000 Playthinks ~ 337/338 Scanning art/ Scanning banks ATM middles ~ Mental problem (3x3 and 4x4 square grids) MAP ~ Cut a parallelogram into two trapezia ~ Can you cut a triangle into 4 quadrilaterals and a triangle? Can you cut a triangle into quadrilaterals only, without putting new corners on the sides of the triangle? WORCS ~ Visualisations	ATM 40 Problems ~ p6 Isosceles triangles ATM (We can work it out) ~ Triangle L5/6 MAP ~ 3x3, 4x4, 5x5 dotty paper activities ~ Tesselating triangles (proving the sum of angles in a triangle) ~ Walk around chalk diagrams on the playground to identify alternate and corresponding angles ~ Angles in polygons Mymaths Angler Game Measuring Angles Angle Sums Reasoning Parallel Lines Interior Exterior	MAP ~ Cabri Geometer / Geometer's Sketchpad - see below... Cabri / JJackson ~ Angles in quadrilaterals ~ Corresponding and alternate angles ~ Angles outside triangles ~ Quadrilaterals by reflecting triangles ~ Quadrilaterals by rotating triangles HORN, Cornwall ~ Alternate and corresponding angles ~ Angles in a triangle ~ Geometrical visualisations 2	~ Spokes OHTs: ~ clock (30°) ; ~ compass rose (45°) , ~ 90° spray ~ Pattern Blocks ~ 3x3 , 4x4 , 5x5 dotty paper MAP ~ Generic assessment criteria	Find 2 shapes with an area of ___ but with different perimeters. Extend to volume and surface area. Why are these called alternate angles? Why are these called corresponding angles? How do you know this is true?	MAP – Level Ladders ~ Geometrical reasoning Written explanations Oral explanations Physical resources