Perimeter is adding together all the sides so 18+12+15+16, which is 61 yds.
Area is the inside, for rectangles that’s found by multiplying the length and width, which is 12 x 16, which is 192. For triangles that’s found by multiplying one half times the base times the height, which is 1/2 x 18 x 3, which is 27.