lo: to measure and calculate perimeters of polygons
TRANSCRIPT
![Page 1: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/1.jpg)
LO: To measure and calculate perimeters
of polygons
Some of the clip art used in this presentation is licensed from the Clip Art Gallery on DiscoverySchool.com
![Page 2: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/2.jpg)
Talk Partners’
• What are polygons?
• How many types can you list?
![Page 3: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/3.jpg)
Look at this ‘L’ shape:
• How would you calculate the distance around this shape?
• What is the correct mathematical term for this?
![Page 4: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/4.jpg)
Perimeter
• When we measure the distancearound a shape, we call it the perimeter.
• We measure the perimeter using the length and breadth measurements
![Page 5: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/5.jpg)
The perimeter is found by adding up all the length and breadth measurements.
+ +
+ +
Length
Length
Breadth
Breadth
![Page 6: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/6.jpg)
Can you find the perimeter for this shape?
12 cm
5cm
![Page 7: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/7.jpg)
Answer
Add up all the length and breadth measurements:
12cm + 12cm + 5cm + 5cm
= 34cm!
![Page 8: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/8.jpg)
• We can write this in another way:“Twice the length plus twice the breadth”
• This is often written as:2 X l + 2 X b
• Can you tell me why?
![Page 9: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/9.jpg)
When calculating the perimeter of a rectangle do we need to
measure all the side?
Talk Partners’ about your ideas and be ready to feedback to
class!
![Page 10: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/10.jpg)
• Can you think of any other shapes where you would not need to measure every side in order to work out the perimeter?
• Can you express the perimeter of these shapes in words and in letters?
![Page 11: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/11.jpg)
CHALLENGE:Can you find the perimeter for this shape?
7cm
7cm
5cm
5cm
3cm
3cm
3cm
3cm
3cm 3cm
3cm 3cm
![Page 12: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/12.jpg)
How did you work out the answer?
Can you express this perimeter in words and letters?
![Page 13: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/13.jpg)
How do we work out perimeters with missing lengths?
What are the perimeters of these irregular polygons?
![Page 14: LO: To measure and calculate perimeters of polygons](https://reader031.vdocuments.us/reader031/viewer/2022020910/6200b6fcd722d256b947cd94/html5/thumbnails/14.jpg)
‘Have a go…’A.
B.
C.