Transcript AREA

MADE BY NORBERT GAUCI
Class 4.1
1
AREA OF A PARALLELOGRAM



6cm

10cm
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
= 60cm2
2
AREA OF A KITE


diagonals
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
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)
= 30cm2
3
AREA OF A TRAPEZIUM
a

h


b
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
= 24cm2
4
AREA OF A RHOMBUS

diagonals



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)
= 60cm2
5
AREA OF A TRIANGLE
B

h
A
D
b
C

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 38O
=
10.8cm2
380
7cm
6