Circle of Life
If we want to find a circle's circumference, we can use 2 pi r or pi d.
(Where the diameter d goes from one side to the other and pi's a bit bigger than three).
If we then want to determine its area then the formula we needs' pi r squared.
(pi's still roughly three, the radius r's half od d) and now we are fully prepared...
For the Circle of Life
And to work out its size:
The distance around it,
The space it occupies.
And we can use it again
(For the rule still applies)
'Cause there's plenty more circles
Than the Circle of Life
A semicircle has half the area,
For a quadrant we divide it by four,
The perimeter consists of an arc and straight lines
(The straight lines are often wrongly ignored).
We have several ways to write down our answers
For a rough guide we can take pi as three
Significant figures are good, 'in terms of pi's even better,
There's no loss of accuracy...
It's the Circle of Life,
We can work out its size:
The distance around it,
The space it occupies.
And we can use it again
Because the rule never lies
There's plenty more circles
Than the Circle of Life.
(Where the diameter d goes from one side to the other and pi's a bit bigger than three).
If we then want to determine its area then the formula we needs' pi r squared.
(pi's still roughly three, the radius r's half od d) and now we are fully prepared...
For the Circle of Life
And to work out its size:
The distance around it,
The space it occupies.
And we can use it again
(For the rule still applies)
'Cause there's plenty more circles
Than the Circle of Life
A semicircle has half the area,
For a quadrant we divide it by four,
The perimeter consists of an arc and straight lines
(The straight lines are often wrongly ignored).
We have several ways to write down our answers
For a rough guide we can take pi as three
Significant figures are good, 'in terms of pi's even better,
There's no loss of accuracy...
It's the Circle of Life,
We can work out its size:
The distance around it,
The space it occupies.
And we can use it again
Because the rule never lies
There's plenty more circles
Than the Circle of Life.