• Recognise equivalent approaches
• Use correctly the vocabulary, notation and labelling conventions for lines, angles and shapes
• Identify parallel and perpendicular lines; know the sum of angles at a point, on a straight line and in a triangle; recognise vertically opposite angles
• Identify and use angle, side and symmetry properties of triangles and quadrilaterals; explore geometrical problems involving these properties, explaining reasoning orally, using step-by-step deduction supported by diagrams
• Recognise efficiency in an approach
• Record solutions and conclusions
• Identify alternate angles and corresponding angles; understand a proof that:
(i) the sum of the angles of a triangle is 180º and of a quadrilateral is 360º;
(ii) the exterior angle of a triangle is equal to the sum of the two interior opposite angles.
• Solve geometrical problems using side and angle properties of equilateral, isosceles and right-angled triangles and special quadrilaterals, explaining reasoning with diagrams and text; classify quadrilaterals by their geometrical properties
• Look for and reflect on other approaches
• Distinguish between conventions, definitions and derived properties
• Explain how to find, calculate and use:
(i) the sums of the interior and exterior angles of quadrilaterals, pentagons and hexagons;
(ii) 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, justifying inferences and explaining reasoning with diagrams and text