Mensuration

1
Mensuration

• Objective
• Perimeter and area of shapes made from triangles
  and rectangles

2
Does anybody know what perimeter is?
The perimeter of a shape is all the way around
the shape.
3cm
3cm
3cm
3cm
Perimeter 3333 12cm
3
On your white boards find the perimeter of these
shapes
4
8cm
5
16cm
6
12cm
7
10m
4m
4m
10m
28m
8
51m
8m
2m
5m
5m
8m
3m
10m
9
4mm
6mm
5mm
10mm
42mm
10
Does anybody know what area is?
Area is the amount of space inside a shape.
Area of a rectangle
Area of a rectangle length x width
Area length x width Area 5cm x 3cm Area
15cm²
11
On your white boards find the area of these
rectangles
12
10cm
6cm
60cm²
13
2mm
24mm²
12mm
14
23km
2km
46km²
15
2m
82cm
1.64m² or 16400cm²
16
Area of a triangle
----------------------------------------
Area length x height
_____________ 2
Height
-----------------------
Length
Example Find the area of this triangle
Area 20cm²
17
On your white boards find the area of these
triangles
18
10m
10m
50m²
19
6m
9m
27m²
20
5km
3km
7.5km²
21
10mm
8mm
8mm
9mm
36mm²
22
Could you find the area of this shape?
4cm
48cm²
30cm²
Area 30cm² 48cm² Area 78cm²
23
Could you find the area of this shape?
10m
50m²
5m
5m
10m²
14m
4m
Area 50m² 10m² Area 60m²