Home Page

Thursday 30th April

Thursday 30th April


Well done for all your work with the circle investigation yesterday. The first thing we are going today is to look at your results. There were lots of children who were able to email their results to me, so have a good look, and compare their results to yours.


First, there were three children who sent their results as a text email, so here are the results that Georgia, Oliver and Jarrad got:


Georgia's results

Object 1: cup 1
Circumference: 25cm
Diameter: 8cm
Circumference ÷ diameter: 3.125

Object 2: cup 2
Circumference: 29cm
Diameter: 9cm
Circumference ÷ diameter: 3.222

Object 3: bowl
Circumference: 37cm
Diameter: 12cm
Circumference ÷ diameter: 3.083

Oliver's results
Object 1: Cake Tin
Circumference = 43cm
Diameter= 13.6cm
Circumference ÷ Diameter = 3.16

Object 2: Mug
Circumference = 32cm
Diameter = 10cm
Circumference ÷ Diameter = 3.2

Object 3 : Tin of Soup.
Circumference = 23cm
Diameter = 7.4cm
Circumference ÷ Diameter = 3.1


Jarrad's results
Circle 1 candle holder
Circumference 43.4cm
Diameter 14.2cm
Circumference ÷ diameter 3.056

Circle 2 alexa
Circumference 26.5cm
Diameter 8.2cm
Circumference ÷ diameter 3.231

Circle 3 cellotape
Circumference 19.7cm
Diameter 6.3cm
Circumference ÷ diameter 3.126

Circle 4 mom's pot of glitter
Circumference 11.3cm
Diameter 3.5cm
Circumference ÷ diameter 3.228


Some children sent in photographs of their results, so here are the pictures:

Picture 1 Berry's results
Picture 2 Kirsty's results
Picture 3 Louie's results
Picture 4 Summer's results
Picture 5 Josh B's results page 1
Picture 6 Josh B's results page 2
Picture 7 Kai's results
Picture 8 Freddie's results
So, what do all these results mean? Well I've made a video for you to watch, in which I discuss your results and what they mean. Here it is:

Circle investigation: what do the results tell us?

Still image for this video

When you did your investigations yesterday, what you were really doing was discovering a special number called "pi", which is always the same, no matter what size the circle is. We can use the value 3.142 for pi, which is close enough for our needs. Here are the rules I showed you in the video:


circumference = 3.142 x diameter


diameter = circumference ÷ 3.142


See if you can use these rules to have a go at the activity I've set for you on My Maths. Good luck, and thanks for doing this lesson. Mr M.