1. p is the symbol used for this special number Pi is its name (Say it as `pie')
p comes from working with circles.
p is the ratio of the circumference of a circle to its diameter.
This means that you can work out p by dividing distance around a circle by the length of its diameter.

2. It works for every single circle in the world
FACT

3. ``May I have a large container of coffee?''
The strange thing is that the answer you get can only ever be approximate - that is, you can never have an exact value for pi. This has fascinated mathematicians for a very long time and they have kept trying to find ways to calculate values for pi that are more accurate.
p =   26535   89793   23846   26433   83279   50288   41972   ...
``May I have a large container of coffee?''

4. ``Now I will a rhyme construct,
By chosen words the young instruct.
Cunningly devised endeavour,
Con it and remember ever.
Widths in circle here you see,
Sketched out in strange obscurity.''

5. To find the circumference and area of a circle
The Circle
Learning Objective:
To find the circumference and area of a circle

6. Circumference
circumference
Circumference =
π × diameter
diameter

7. Area
Area
= π × radius × radius
= π × radius2
radius
area

8. Circumference is
π x diameter
Area is πr2

9. Example 1 Circumference = π × diameter Circumference = π × 4
Find the circumference of this circle
circumference
Circumference
= π × diameter
4cm
Circumference
= π × 4
= 12·57cm (2 d.p.)

10. Example 2 Circumference = π × diameter Circumference = π × 16
Find the circumference of this circle
circumference
Circumference
= π × diameter
8cm
Circumference
= π × 16
= 50·27cm (2 d.p.)

11. Example 1 Area = π × radius × radius Area = π × 7 × 7
Find the area of this circle
Area
= π × radius × radius
7cm
Area
= π × 7 × 7
= 153·94cm² (2 d.p.)
area

12. Example 2 Area = π × radius × radius Area = π × 5 × 5
Find the area of this circle
Area
= π × radius × radius
10cm
Area
= π × 5 × 5
= 78·54cm² (2 d.p.)
area

13. Find the circumference and area of this circle
Question 1
Find the circumference and area of this circle
Circumference = π × diameter
Circumference = π × 9
= 28·27cm (2 d.p.)
9cm
Area = π × radius × radius
Area = π × 4·5 × 4·5
= 63·62cm² (2 d.p.)

14. Find the circumference and area of this circle
Question 2
Find the circumference and area of this circle
Circumference = π × diameter
Circumference = π × 12
= 37·70cm (2 d.p.)
6 cm
Area = π × radius × radius
Area = π × 4·5 × 4·5
= 113·10cm² (2 d.p.)