Question

The diagram shows a sector of a circle of radius 18cm

Length of arc is 4pi
Work out the value of x°

Answer 1

40º

Explanation:

First we can find the circumference and the formula for that is diameter × π

diameter is radius times 2

``18*2`

`36`

And we put pi in front of it to find circumference

`36\pi`

Since the arc in the picture is
`4\pi` we just divide 36π by 4π to find what portion of the circle in the picture

36π/4π=9π

Now we know that this is one ninth of the circle and since a full circle is 360 º we just divide 360 by 9

360/9

40º

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