The perimeter of a triangle is the sum of all the sides;
Hence, adding all the sides, you have
3.6g - 2.5h + 8.5g + 6.4k + 3.3k + 2.6h
Collect like terms
3.6g + 8.5g + 6.4k + 3.3k - 2.5h + 2.6h
12.1g + 9.7k + 0.1h
9.7k + 0.1h + 12.1g
Hope this helps. Don’t forget to mark my answer the brainliest if you’re satisfied with it.