Perimeter Made Simple

Eric Marquette

Hello and welcome back to Functional Skills with Educationwise. I'm Eric Marquette, and today we're gonna make sense of something that, honestly, comes up more often than you might think—perimeter. Now, if you’re thinking, “Perimeter? That’s just a maths word I heard ages ago,” you’re not alone. But stick with me, because it’s actually pretty straightforward, and, well, surprisingly useful.

Eric Marquette

So, let’s start simple. Perimeter is just the total length around the edge of a shape. That’s it. If you imagine walking all the way around your garden, or, I dunno, tracing the outline of your phone with your finger, you’re basically measuring the perimeter. It’s the distance all the way around.

Eric Marquette

Now, for regular shapes—like rectangles and squares—the formulas are, well, about as friendly as maths gets. For a rectangle, you add up all the sides, but since opposite sides are equal, you can just do two times the length plus two times the width. For a square, it’s even easier: four times the length of one side. That’s it. Four sides, all the same, so just multiply one by four.

Eric Marquette

Actually, this reminds me—back in school, we had this massive football pitch, and our PE teacher, Mr. Davies, made us measure it for some reason. I think it was a maths lesson disguised as exercise, honestly. We had to walk the whole way round with a measuring wheel, and then add up all the sides. That was the first time I realised, “Oh, perimeter isn’t just a word in a textbook, it’s literally the fence around the pitch.” So, yeah, it’s not just for exams—it pops up in real life more than you’d expect.

Eric Marquette

Alright, so let’s get a bit more specific. If you’ve got a rectangle, like we said, it’s two times the length plus two times the width. Say your garden is 5 metres long and 3 metres wide. The perimeter? Two times five is ten, two times three is six, add them together, you get sixteen metres. That’s how much fencing you’d need to go all the way round.

Eric Marquette

For a square, it’s even simpler. If each side is, let’s say, 4 metres, then four times four is sixteen metres. Easy. Now, triangles are similar. You just add up all three sides. So if your triangle has sides of 3, 4, and 5 metres, the perimeter is 3 plus 4 plus 5, which is 12 metres.

Eric Marquette

Now, circles—this is where things get a bit more interesting. The perimeter of a circle is called the circumference. There are two main formulas you might see: C equals two times pi times the radius, or C equals pi times the diameter. So, C = 2πr or C = πd. And if you’re thinking, “Wait, what’s pi again?”—it’s that funny Greek letter, looks a bit like a wobbly table, and it’s roughly 3.14. I always remember it as the number you use when you’re dealing with circles, and, well, pies, I suppose. Sorry, that’s a terrible joke, but you get the idea.

Eric Marquette

So, if you’ve got a circle with a diameter of 10 metres, the circumference is pi times 10, which is about 31.4 metres. Or, if you know the radius—say, 5 metres—you’d do two times pi times five, which, again, gives you about 31.4 metres. It’s the same either way, just depends on what measurement you’ve got.

Eric Marquette

Now, let’s talk about why any of this matters. Imagine you’re helping out at your local school, and they want to put a border around the new playground. The playground’s a rectangle, 20 metres long and 10 metres wide. How much material do you need for the border? Well, perimeter to the rescue. Two times twenty is forty, two times ten is twenty, add them up, and you get sixty metres. So, you’d need sixty metres of whatever material you’re using—wood, metal, plastic, whatever—to go all the way round.

Eric Marquette

And that’s just one example. Whether you’re putting up a fence, laying out a running track, or even just buying trim for a room, knowing how to work out perimeter saves you time, money, and, honestly, a lot of headaches. It’s one of those skills that, once you’ve got it, you’ll find yourself using it in all sorts of places.

Eric Marquette

Alright, that’s perimeter made simple. If you found this helpful, or if you’ve got a story about using perimeter in your own life—maybe you measured your own football pitch, who knows—let me know. And if you’re keen to keep building your maths skills, stick around for future episodes. We’ll keep breaking things down, one step at a time. Thanks for listening, and I’ll catch you next time.