Tagged: pi

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Leave it all in terms of Pi until the last minute

Today I heard this golden nugget of advice from the most talented maths teacher I’ve ever met… When teaching students to do calculations involving Pi, leave it all in terms of Pi until the very last minute. Rather than the workings for volume of a cylinder of radius 10cm and height 20cm being: Pi X 10^2 = 314.159… 314.159… X...

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Buffon’s Needle- a mysterious probability activity

Buffon’s Needle is a wonderful probability experiment you can do with a class that has a most┬ásurprising┬áresult. Out of a seemingly ordinary, unspectacular experiment involving dropping a pencil between a pair of parallel lines, the relative frequency is related to pi! Here is a superb website that explains the experiment and gives a derivation of why the results tend towards...

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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...

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How Normal is Pi?

I designed this investigation to challenge a high-flying year 9 group to see if they could apply the principles of relative frequency to explore whether pi is a normal number. Normal numbers are irrational numbers where, considering the digits after the decimal point, the likelihood of the next digit being a 1 is as likely as it is being any...

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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...

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How fast are the planets?

Which planet is travelling the fastest in its orbit? Which is slowest? Is there a link between distance from the sun and how fast the planets travel? Start by asking the students to come up with what information they would need to work this out. You can then take their ideas and if necessary lead them to working out each...