# Perimeter

We have been learning about perimeter in class this week.

Perimeter is the distance around the outside of a shape.

For example, here is how you might calculate the perimeter of our current class novel, The One and Only Ivan.

Β 19cm + 19cm + 12cm + 12cm = 62cm

OR

(19cm + 12cm) x 2 = 62cm

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We have been focussing on:

• Understanding what perimeter is
• Identifying when you might need to know the perimeter of something
• Measuring accurately
• Deciding the appropriate unit of measurement to use
• Using efficient addition skills to calculate the perimeter.

*****

Yesterday in class students worked in pairs to calculate the perimeter of some objects in the classroom. We then shared our work to compare our results.

Today we calculated the perimeter of some outdoor objects, including the basketball court, sandpit, rock climbing wall boundary and the new downball court.

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## 29 thoughts on “Perimeter”

1. Dear 4KJ and Students,

I really enjoyed this topic and have never said no to this topic because I love doing perimeter and I hope everyone else does too.

• Hi Connor,

Thanks so much for your comment on the blog. It is so good to hear you like to do Perimeter.

I do to because it can give me a bit of a challenge. I like a good challenge but not one that is way to hard.

I have had a really fun day and can’t wait to do more Perimeter on Monday again.

I think that everyone likes to learn new things like I do and there is a lot coming up ahead of us in Term 4.

Got 2 Gallop,
liv π π π

• Hi Connor,

I think that your comments you have been leaving on this blog post are great and I can’t wait to see more from you.

It will be so good for you to keep leaving these comments and maybe even share some things you know about Perimeter.

Got 2 Gallop,
Liv π π π

2. Dear 4KJ,

Q.What have you learnt about perimeter?
A. My answer is I have learnt that Premier is when you are mesmerising the outside of the shape or object.

Q.When might you need to know the perimeter of something?
A.You might need to know the perimeter when you are drawing or Building

The challenge: Measure and calculate the perimeter of something and leave your answer in your comment. Donβt forget to include your working out
A. I meshred my book and it meshred for the long way it got 20cm and the bottem is 13cm

These is the working out 20+20=40 40+13=53 53+13=66

Love From,
Chloe

• Hi Chole,

What a great comment you left. I think that it was so good that I could read it again and again.

The answers you put to the questions were great. and I learnt some of the sames things as you.

Got 2 Gallop,
Liv π π π

3. Hi Everyone,

Great Post!

I have enjoyed learning about Perimeter in class lately and in the last few lessons I have started to understand and enjoy it.

I now have some Answers for the questions:

Q.1) What have you learnt about perimeter?

A.1) What I learnt about Perimeter is that you can measure the perimeter of the shapes sides.

Q.2) When might you need to know the perimeter of something?

A.2) I think we would to use it if we were to measure a block of land for a house to get built on the block, that is what I think we need to know what the perimeter is on something!

Bye for now,
Eden π

• Hi Eden,

Thanks so much for your great comment. It was so nice of you to leave it for us to read.

I think that Perimeter is a great subject for maths and it is a good challenge for us all to learn more about.

Even though I have only been here for one day I still understand a lot but need some more practice to learn even more.

It would be so good if everyone could get Perimeter by the end of next week and can tell Miss Jordan and Miss Smith right?

I think that you should keep up these great comments and replies to everyone. Thanks!

Got 2 Gallop,
Liv π π π

4. Dear 4KJ,

I have learnt alot about perimeter I loved doing the activity outside where we had to, measure the plank around the rock climbing wall.

Sincerly

Jacob π

• Hi Jacob,

It was very good to see a comment from you on our blog. I think that it would have been fun to do that and I wish I was there although I liked Queensland better.

I think that your comment was very good and it would be even better to see more from you.

Got 2 Gallop,
Liv π π π

5. Hi Everyone,

Great Post Miss Jordan! Here are my answers:
A.1) I have learnt that Perimeter it the outside of an object not the inside.

A.2) You might need to know the perimeter of your room and your bed so you know if you can put your bed in.

What have you learnt about Perimeter?

Kind Regards,
Lee π

• Hi Lee,

Thanks so much for your comment. It was so nice of you to leave it and I am glad that you left it.

I think that we are getting some really good comments on our blog and I am glad that that is so.

Perimeter is a great thing to learn about and it is an awesome thing itself. (For maths.)

Yes I already new that perimeter was the outside of a shape so that is crossed of the know it all list.

And I think that it was good how you gave a different answer to everyone elses.

Got 2 Gallop,
Liv π π π

6. Hi 4KJ,

I have really enjoyed learning about Perimeter in class. I really liked measuring the perimeter of the rock-wall and also the down-ball court.

Q.1 What have you learnt about perimeter?

A.1 I have learnt that you can measure the perimeter of something in all different measurements units.

Q.2 When might you need to know the perimeter of something?

A.2 If you are putting in a swimming pool you will need to know how big to make it if you are putting in your backyard and you also need to know where you would put it.

From Mitchell π

• Hi Mitch,

Thanks so much for your awesome comment. It was so nice of you to leave it and I am glad that it has happened.

I think that you may have made a little mistake which is fine but for now I will tell you what it was:

When you said that f you are putting in a swimming pool you will need to know how big to make it

You should have said you need to know how big to make the HOLE. But you said it.

It doesn’t matter I just thought you may have wanted to know.

Got 2 Gallop,
Liv π π π

7. Dear 4KJ,

Q. What have you learnt about perimeter?
A. I learnt that you can use perimeter for almost everything.

Q. When might you need to know the perimeter of something?
A. You might need to know the perimeter of something in case you are building a new house.

Sophie

• Hi Sophie,

Great comment!

I have loved learning about perimeter last week, it was lots of fun when my group had to measure the rock climbing wall boundary and the new downball court! And of course, it sure would of been fun, to do the basketball court and the sand pit with your group!

I also learnt that you can use perimeter for almost anything and I also learnt that perimeter is very fun to use at home, and at school. But you would have to use a ruler or a tape measure to measure, things!

I think you are absolutely right, we would have to know the perimeter of something in case you’re building a new house.

Happy Blogging, π
Meg

• Hi Meg,

Thanks so much for your awesome comment. It was very nice of you to leave it.

Perimeter is a great subject and we are so lucky to be doing it.

Got 2 Gallop,
Liv π π π

8. Dear 4kj,

I am looking forward to seeing what the next three weeks have in store for the 4kj students and me.

Q.1) What did you learn in perimeter.

A.1) I have learnt that you can use perimeter in a lot of different ways.

Q.2)When might you need to know the perimeter of something.

A.2) You might need to know the perimeter of something when you have just moved house and you are figuring out where everything is going to go in side your bedroom,loungeroom aor kitchen

sincerely,
Mitchell,s

• Hi Mitchell,

Thanks so much for your comment. It was very nice of you to leave it and I am glad that you did.

I think that Perimeter was a great subject and I am glad we can now work on area because that is fun too.

Got 2 Gallop,
Liv π π π

9. Hello 4KJ,

Reading through your post and discoveries about perimeter made me think, I wonder where the word originated. I found it came from the Greek “perimetron” meaning “around” (peri) “measure” (metron). Perimeter is the measure around the edge of a shape.

The screen on my computer has a rectangular display. The top and bottom lengths are 60cm each and the sides are 33cm each. That gives a perimeter of 186 cm. No matter how many sides there are, if they are straight we only need measure with a ruler and add each.

Next I looked at a round table top but, being round, there were no straight sides so a ruler wouldn’t work. Imagine, a long time ago, a number of people (including the Ancient Greeks) worked out how to do it even though a circle doesn’t have any straight sides. For the Greeks, it was as simple as a piece of PI but you’ll learn more about that in the future.

Keep exploring maths. It’s something we use every day even if we don’t realise it.

Ross Mannell
Teacher (retired), N.S.W., Australia

*There is a way you can get a close idea of the perimeter (circumference) of a circle. Use a piece of string (or cotton). Lay it around the outside of a circle then use a ruler to measure the length of the string.
With a ruler and some string, you can work out the approximate perimeter of some pretty weird shapes.

• Hi Ross,

Thanks so much for your comment on our blog. It was very nice of you to leave it and I am glad you got the time to do it.

I am so glad that there is am comment from you because I think all of your comments are great.

I must say I have no idea how you get the time to leave all of these comments for everyone.

It is so interesting to learn about perimeter and I am so happy that this is our topic.

It is interesting how you measured your computer screen. I think that that it cool.

When I did SOME perimeter on the weekend I measured my whole computer closed. I also did my other one because it is different. (By the way I have a school one and a home once in case you were wondering.)

I wonder how hard it was to measure a round table. It sounds like a lot of fun though and a challenge.

Thanks again for your great comment and keep it up!

Got 2 Gallop,
Liv π π π

• Hello Live,

It seems, like me, you are keen on the things computers can do for us. I also have more than one computer. In my case, one is used to edit video and photos as well as writing comments like this. A second is responsible burning up to 7 CDs/DVDs at a time and a third printing photos and graphics on CDs/DVDs. This allows me to work on more than one task at a time, something important when I have to work on tasks for schools and community groups.

Today (Wednesday), I will be joining the volunteer staff of my favourite animal sanctuary (Potoroo Palace where I take many of my animal photos). We will be heading out to sea hoping to find some migrating whales heading south for summer. If I can take any good photos, I may be able to share them but sometimes you don’t see much more than a quick surface to breathe.

Keep exploring maths. There always seems to be more to learn. π

Ross Mannell
Teacher (retired), N.S.W., Australia

• Hi Ross Mannel,

4KJ really appreciate the comment you left on our blog. Thank you!

Perimeter is really fun to learn. One of my favourite things about it, is working it out when some of the lengths are blank. We did some of that yesterday.

It is great that you did some perimeter work yourself. – measuring your computer screen.

I am sure 4KJ will keep improving there maths and perimeter skills!

What is you favourite maths topic?

Got 2 Gallop,
Paris π

10. Hi 4KJ,

What a fantastic post about perimeter! One of my favourite maths topics in fact.

Q1. What have I learn’t about perimeter?
A1. I have learn’t that not all lengths have to have a number, they can be blank and you have to work it out.

Q2. When might I need to know the perimeter of something?
A2. You might be getting a pool in your backyard and will need to know what the perimeter is.

Got 2 Gallop,
Paris ♥

• Hi Paris,

Thanks for your comment. It so was good of you to have the time to leave it for us to see.

I think that everyone is leaving great comments on here.

Got 2 Gallop,
Liv π π π

11. Dear 4KJ,

Great post!

I have learnt how to figure out the perimeter of objects really quickly.

You might need to know the perimeter of something when a car factory is making a car so the same type of car is the same size.

I measured the base of my notebook an it was 19cm by 28cm.

I worked it out like this:

19cm+19cm=38cm
28cm+28cm=56cm
38cm+56cm+94cm

What has been your favourite lesson on perimeter so far?

From,
Harry π π

12. Hi 4KJ,

Great post Miss Jordan! π

Q. What have you learnt about perimeter?

A. I have learnt a lot of things about perimeter before we even started learning about it I didn’t even know what it was!

Q. When might you need to know the perimeter of something?

A. You would need to know the perimeter of when you are building a house. We had to do that when we moved house!

A. Say that you bought a couch you would need to know the perimeter of space you have so then you know what couch to buy!

A. You would also need to know the perimeter of the space if you were going to get a new bed, so then you know what kind of bed to buy.

I haven’t measure something yet but I will leave a comment and show you what I have done! π

See you soon,
Eb π

13. dear 4KJ,
how exciting learning about perimeter! lots of things have perimeter such as a yard, book, house or even a fridge.i hope you have had fun learning about them! i certainly love perimeter! good luck with the rest of the year as well. π
from Sienna

14. Hello Paris,

You probably know I like many subjects and topics so it would be very hard to choose one favourite maths topic. Sometimes it’s whatever I am working on at the time. Sometimes it’s working out how to do something or seeing if there is a maths solution to a problem. Rather than one topic, my favourite part of maths is working out how. π

As an example, I wanted to have passwords that would be very hard for people to work out. I used a spreadsheet (maths worksheet on a computer) to work out a way to make a 12 character password. You enter a six letter word then a number and it will make up a password. With the same six letter word and number, it will always give the same password. Change the six letter word and/or number and the password changes. I’ll give you a sample password.

I enter number 4 as you are in Year 4. I now use 4km4kj as the six letter word. Here is the password I get…

>c@=K?8ia@5′

You can see it would be very hard to guess the password but, if you know the number and six letter word and have my spreadsheet, you will always get the same password. Itβs easier to remember the six letter word and number than the password it makes. I have some favourite six letter words (theyβre secrets).

I can have a pretty weird mind. π

Ross Mannell
Teacher (retired), N.S.W., Australia