So first of all, you need to work out the two missing sides.
To work them out you need to do: 30 - (15+12) which would be 3.
And: (19+4) - 17 which would be 6.
Then you add all the sides together.
30 + 15 + 12 + 3 + 19 + 17 + 4 + 6 which equals a total of 106
So your answer is 106 yds