To work out the length of an arc, we use the following equation:
<em>(r stands for radius)</em>
So just substitute in the values to get the arc length of the first sector:
(angle = 40, radius = 12)

For the other sector, the angle will also be 40, since opposite angles are the same. So to get the arc length, we substitute in:
(angle = 40, radius = 5)

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Now to get the perimeter, we add up all of the arc lengths and side lengths:


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Answer:
Perimeter =
cm or 45.87cm rounded to 2 decimal places.