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Find the perimeter.
Areas
Grade 7 - CIC
10 Apr 2023
Area of a Rectangle
3 1
24 3
3
3
612
X =X =X =
B Ah
B
B
hh
B
h
B = base
h = height
Must learn formula !
1 cm
Area = base x heightA = B x h
Find the area of each rectangular shape below.
100 m
50 m
120 m
40 m
1 2
34
5
8½ cm
5½ cm
90 feet
50 feet
210 cm
90 cm
Not to scale.
5 000 m2
4500 ft2
4 800 m2
46.75 cm2
18 900 cm2
base
height
base
height
Area of a Parallelogram
The area of a parallelogram
= the area of a rectangle on the
same base.Area = base x height
Area = base x height
8 cm
14 mm
1.5 m
12 cm
5 mm
2.1 m
Find the area of each parallelogram below.1
2
3Area = 8 x 12
= 96 cm2
Area = 14 x 5
= 70 mm2
Area = 1.5 x 2.1
= 3.15 m2
base
height
Area of a triangle = ½ base x height
Area of a Triangle
The area of a triangle = ½ the area of the surrounding rectangle/parallelogram
Area of a Triangle
rectangle area = 2 + 2 triangle area = ½ rectangle area
base
height
Area of a triangle = ½ base x height
The area of a triangle = ½ the area of the surrounding rectangle/parallelogram
Area = ½ x 8 x 9
= 36 cm2
Area = ½ x 10 x 12
= 60 cm2
Area = ½ x 14 x 16
= 112 cm2
Area = ½ x 3.2 x 4.5
= 7.2 m2
Find the area of the following triangles.
8 cm 10 cm
14 cm
12 cm9 cm 16
cm
Area = ½ b x h
3.2 m
4.5 m
7 mm
5 mm
Area = ½ x 7 x 5
= 17.5 mm2
The Area of a Trapezium
Area = ½ the sum of the parallel sides x the perpendicular height
A = ½(a + b)h
a
b
h
b
½h
a
Area of trapezium = area of parallelogram
A = ½(a + b)h
The Area of a Trapezium Area = ½ the sum of the parallel sides x the perpendicular height
A = ½(a + b)h
a
b
h½ah
½bhArea = ½ah + ½bh = ½h(a + b)
= ½(a + b)h
Area = ½ (8 + 12) x 9
= ½ x 20 x 9
= 90 cm2
Area = ½(7 + 5) x 6
= ½ x 12 x 6
= 36 cm2
Find the area of each trapezium
1
8 cm
12 cm
9 cm
25 cm
7 cm
6 cm
3
5 cm
3.9 cm
7.1 cm
Area = ½(3.9 + 7.1) x 5
= ½ x 11 x 5
= 27.5 cm2