This activity is about finding the circumferences and areas of circles using a calculator.

We need to learn the two important formulae below using the radius of a circle (r)

Circumference of a circle = 2 π r

Area of a circle = π r^{2}

**Examples**

Find the circumference and area of a circle of radius 6 cm.

π is usually taken to be 3.142, but your calculator should have the π button on it which will make your calculations more accurate. Once you've done the first part of the calculation, just tap in **x π** and then **=** and you should get the correct answer. Test it out with the examples below!

**Answers**

**Circumference = 2 π r **= 2 x π x 6 = 12 x π = **37.7 **cm (1 dp)

**Area = π r ^{2}** = π x 6

^{2}= π x 36 =

**113.1**cm

^{2}(1 dp)

On to the questions now!