1 MADE BY NORBERT GAUCI Class 4.1

2 AREA OF A PARALLELOGRAM Its opposite sides are parallel. Opposite sides and opposite angles are equal. Its diagonals bisect each other Area of a parallelogram = base x perpendicular height Example: Lets find the area of this parallelogram if the parallel sides are 10cm long and its height is 6cm. Area of parallelogram = base x height = 10 x 6 = 60cm 2 6cm 10cm

3 AREA OF A KITE A quadrilateral with two pairs of equal adjacent sides. Its diagonals bisect each other at right angles. The opposite angles between the sides of different lengths are equal. Area of a kite = ½(product of diagonals) Example: What is the area of the kite if it diagonals are 5cm width and 12cm long. Area of a kite = ½(product of diagonals) = (5 x 12) = 30cm 2 diagonals

4 AREA OF A TRAPEZIUM Has two parallel sides only Area of a trapezium = ½(a+b) x height a + b is the sum of the two parallel sides Example: Find the area of a trapezium if a = 5cm, b = 7cm and the height is 4cm. Area of a trapezium = ½(a+b)h = ½(5+7)4 = 24cm 2 a b h

5 AREA OF A RHOMBUS A parallelogram with all sides equal Its diagonals bisect each other at right angles Its diagonals also bisect the angles Area of a rhombus = ½(product of diagonals) Example: Find the area of the rhombus if one diagonal is 10cm long while the other is 12cm. Area of a rhombus = ½(product of diagonal) = ½(10 x 12) = 60cm 2 diagonals

6 AREA OF A TRIANGLE According to this triangle a is the hypotenuse, b is the adjacent and h is the opposite. Area of triangle = ½ ab sinC Example: Find the area of this triangle if one of its side is 5cm and its base is 7cm Area of triangle = ½ ab sinC = ½ (5 x 7) sin 38 O = 10.8cm 2 b c A B C D a h 7cm 5cm 38 0