# Tagged: circle

## Surface area of spheres- an apeeling lesson…

How do you give pupils a beautiful visual picture of why the surface area of a sphere is 4 pi r squared? A super lesson idea I heard recently involved an orange! Give pupils an orange and a blank sheet of paper. They have to draw circles around the orange onto the paper. The idea is that the circles on...

## Where does pi r squared come from? Beautiful demonstration

Here is something a bit special. It’s an amazing Geogebra applet that shows where the formula for the area of a circle comes from. I’ve had pupils cutting circles into sectors before to perform the same proof, but this interactive applet it first class in showing the concept in a visually stunning way and quickly. Top stuff! Click here to...

## It all began when a line met a circle…

I got a bit nervous this week. I had to teach my high-flying year 11s how to solve simultaneous equations algebraically when one is a circle and another is linear. This was the first time I’d taught this topic and one I foresaw as having many potential obstacles to them gaining a good understanding. It links so many areas of...

## Circles are awesome!

Circles are awesome! That is certainly true but it is also the name of a fantastic website showing how circumscribed circles can be constructed. You can also move around the points and see the effects on the circumscribed circle in real time. Visit the Circles Are Awesome website here. Why not work your way through the steps in the presentation...

## Curvy Areas- because every maths teacher needs NRich Maths

If you haven’t seen the NRich Maths website where have you been?! It’s a fantastic source of enriching activities. It’s usually my first port of call when I’m looking for ‘something a bit different’ for my own classes. Many of the resources are interactive and look great on the interactive white board. Each month NRich publishes a ‘virtual magazine’ which...