Know and use the sum of the angles at a point is 360°.

Know that the sum of the angles at a point on a line is 180°.

Know and use:

vertically opposite angles are equal

alternate angles on parallel lines are equal

corresponding angles on parallel lines are equal.

Derive and use the sum of the interior angles of a triangle is 180°.

Derive and use the sum of the exterior angles of a polygon is 360°.

Find the sum of the interior angles of a polygon.

Find the interior angle of a regular polygon.

Apply these angle facts to find angles in rectilinear figures, and to justify results in simple proofs.

e.g. The sum of the interior angles of a triangle is 180°.

Apply these angle properties in more formal proofs of geometrical results.