Pi (π)

Pi, written π, is the number you get by dividing any circle's circumference by its diameter: about 3.14, the same for every circle. So circumference = π × diameter. Its digits never end and never repeat: π is an irrational number.

Depth 1 · Foundation

You know every circle's circumference is about 3.14 times its diameter, that this number is π, and can use it to find the way round a circle.

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Depths of understanding

1
Foundation
You know every circle's circumference is about 3.14 times its diameter, that this number is π, and can use it to find the way round a circle.
Read it
- Pi: Once Round the CircleGeometry Level 1: Shapes and Space
Opens after
Circlesπ compares two lengths of a circle: the way round and the way across.PerimeterThe circumference is a circle's perimeter, its way round.Decimalsπ is about 3.14, a decimal.

Your path here

What's still between you and Pi (π), depth 1, in the order you can learn it.

Where it fits

Builds on

Circles Perimeter DecimalsFractions

This concept

Pi (π)Geometry

Builds onThis conceptCircles Perimeter DecimalsFractions Pi (π)Geometry

Makes these deeper

Once you know Pi (π), come back to these — they'll mean more.

CirclesDepth 2The area of a circle is π × radius × radius.