<span>you can find the </span>area<span> of each triangle, A = 1/2bh or A = 1/2lw, then multiply by the number of triangles, which would be based on the number of sides of the base; or you can take half the perimeter and multiply by the slant height.</span>
to get you answer you would have to add 1 1/2 and 2 1/4, then your equation would be 60 ÷ 3 3/4 , then whatever your total is, multiply that by 40 and that would be your answer