To calculate the area of non-rectilinear shapes
Mathematics - 2D Perimeter and Area
Miss Kim
In this lesson, you will need:
Exercise book or paper
Pencil
2
Image credit: Pixabay
3
Starter Quiz
Recap previous lessons
Estimating areas of non-rectilinear shapes
Independent worksheet
Exit Quiz
Keywords
Area - The amount of space taken up by a 2D shape.
Perimeter - The total distance around the outside of a shape.
Rectilinear shapes - A shape that has straight sides and right angles. It can look like two rectangles that are joined together.
4
Recap
5
5
Comparing area
6
True
False
These rectangles have the same area.
Area = 12 m²
12 m
Comparing perimeter
7
True
False
These two rectangles have the same perimeter.
4 + 5 + 5 + 4 = 18 cm
4 + 6 + 4 + 6 = 20 cm
4 cm
Calculate the area and perimeter of this rectangle.
8
3 km
7 km
Area
7 x 3 = 21 km²
Perimeter
7 + 7 + 3 + 3 = 20 km
9
Estimating areas of non-rectilinear shapes
10
11
How would you calculate the area of this shape?
12
Count and estimate!
8 cm²
1 cm
1 cm
How would you calculate the area of this shape?
13
Count and estimate!
16 m²
1 m
1 m
Let’s estimate!
14
Count and estimate!
20 km²
1 km
1 km
Now it’s your turn!
Let’s estimate
15
Count and estimate!
9 cm²
1 cm
1 cm
Now it’s your turn!
Let’s estimate
16
Count and estimate!
16 cm²
1 cm
1 cm
When might we need to calculate the area of a non-rectilinear shape?
17
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
18
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
19
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
20
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
21
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
22
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
23
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
24
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
25
Image credit: Pixabay
When might we need to calculate the area of a non-rectilinear shape?
26
Image credit: Pixabay
How would you calculate the area of this shape?
27
Count and estimate!
8.5 m²
1 m
1 m
How would you calculate the area of this shape?
28
Count and estimate!
9 cm²
1 cm
1 cm
Now it’s your turn!
Let’s estimate
29
Count and estimate!
13.5 cm²
1 cm
1 cm
Now it’s your turn!
Let’s estimate
30
Count and estimate!
16 m²
1 m
1 m
How would you calculate the area of this rock pool?
31
Image credit: Pixabay
How would you calculate the area of this rock pool?
32
Image credit: Pixabay
Let’s estimate together!
1 m
1 m
Count and estimate!
Let’s estimate together!
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1 m
1 m
Count and estimate!
8 x 4 = 32 m²
32 m² + =
Image credit: Pixabay
Independent worksheet
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35
36
Pause the video to complete your task
Resume once you’re finished
To calculate and measure perimeter
Copy and complete all questions on the independent worksheet before you continue.
You can draw the shapes in your exercise book.
Worksheet Answers
37
Question 1
Estimate the area of this shape.
38
1 m
1 m
Count and estimate!
9 m²
Question 2
Estimate the area of this shape.
39
1 cm
1 cm
Count and estimate!
15 cm²
Question 3
Estimate the area of this shape.
40
1 km
1 km
Count and estimate!
Question 3
Estimate the area of this shape.
41
1 km
1 km
Count and estimate!
30.5 km²
Question 4
Estimate the area of this shape.
42
1 mm
1 mm
Count and estimate!
Question 4
Estimate the area of this shape.
43
1 mm
1 mm
Count and estimate!
45 mm²
44
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