I’m confused on this one

Compare the values they have given you with the diagram. a, b and c are all sides of the triangle they want you to find the perimeter of. Knowing this, all you have to do is add a, b and c. h is not important because you don't count the altitude of a triangle when you calculate perimeter.
12 + 10 + 12 = 34
The perimeter of the triangle is 34 ft.