Answer: the perimeter of this shape is 39mm.
Explanation:
To find the perimeter of a shape, you need to add up the lengths of all its sides. In this case, the given shape has two sides with lengths of 9mm and 30mm. To find the perimeter, you simply add the lengths of the sides together: 9mm + 30mm = 39mm Therefore, the perimeter of this shape is 39mm. Remember, the perimeter represents the total distance around the shape, so it's important to add up the lengths of all the sides.