**Pi **is the name for a very long number: 3.1415926535897932384626433832795028841971...

**The symbol for ****pi** is: π

A scientific calculator has a button 'π' to press if you need to use pi.

**Formula for area of a circle: **

This means pi x radius x radius. (It does NOT mean pi x radius x 2)

**Study and practice**

- Try your hand at changing the area enclosed by a circleThis page on mathopenref.com lets you see how the area of the circle changes as you adjust its radius.
- Quiz yourself on finding the area of circlesThis quiz at aaastudy.com will help you check your understanding of the circle area calculation.

The video explains how to use the pi button on a Casio fx-991 scientific calculator.

1.25 min - how to calculate a circle's area

- Online scientific calculator from Calculator.netTo open the scientific calculator in a new window, you MUST click the link.

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