Geometry Angles at a point added up to 360  Angles on straight line added up to 180  Solve exercises 23 – 27 on page 71

Polygons The exterior angles of a polygon added up to 360 o The sum of interior angles = (2n – 4) x 90 o Solve exercises 7 – 10 on page 72

Parallel lines From the figure a = c (corresponding angles) c = d (alternative angles) b + c =180 o What is the acute angle? what is the obtuse angles? Solve the exercises on page 73

Pythagorth’s theorem In the right-angle triangle the square on the hypotenuse is equal to the sum of the squares of the other sides. a 2 + b 2 = c 2 If the square on one side of triangle is equal to the sum of the squares on the other two sides, then the triangle is right-angled

Solve exercises 5 – 8 on page 74

Symmetry Quadrilateral – Square All sides are equal, all angles 90 o opposite sides are parallel; diagonals bisect at right angle. – Rectangle opposite sides parallel and equal, all angles are 90 o; diagonals bisect each other. – Parallelogram Opposite sides parallel and equal, opposite angles equal; diagonals bisects each other.

Rhombus – A parallelogram with all sides equal, diagonals bisect each other at right angles and bisect angles.

Graphics Display It is useful to represent in equalities on a graph, particularly where two variables are involved. Example: X > 2 ; 1  y  5; x+y  8

Solve exercises 1 – 9 on page 113 Solve exercises