We can solve for the surface area of the triangular prism using the formula below: SA=bh + (s1+s2+s3) H where b for the base, h and H for the height while s1, s2 and s3 for the length of the sides of the equilateral triangles. Solution is shown below: SA=10*9+(10*10*10) *18 SA=90+(1000*18) SA=1,620,000 u²