Mammoth Memory

Arc of a sector

Using the same reasoning about radians we can also work out the length of any arc on a circle.


Work out the length of the arc AB

Work out the length of this circles circumference using radians



Therefore Circumference`=2pi times12` `cm`

                                             `=24pi` `cm`

Logic progresses as follows:

  `24pi=100%`of the circumference

`360^@=24pi` `cm`

  `60^@=x` `cm` 


`360/60` `=` `(24pi)/x`
`x` `=` `(60times24pi)/360`
`x` `=` `(1times24pi)/6`
`x` `=` `4pi`


 Answer: The arc is `x=4pi` `cm` long

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