**1. Why does pi have so many decimal places?**

Piis anirrationalnumber and will keep on going for an infinite number of decimal places with no ending or repeating pattern. Many of the square roots are also irrational numbers. e.g. √3

**2. What is the connection between the diameter and the radius of a circle?**

The diameter is

TWICEthe length of the radius. i.e. d = 2r

ORThe radius is

HALFthe length of the diameter i.e. r = d / 2

**3. How is the diameter of a circle related to the circumference?**

The diameter divides into the circumference just over three times (

pitimes)

**4. What units are used to measure the length of the circumference?**

The units used for the circumference will be the same as those given for the radius or the diameter. (Unless you change them!)