A piece for a board game is shaped like a triangular prism. The piece is 18 millimeters long. The base of the piece is an equilateral triangle with 10 millimeter sides and a height of 9 millimeters. Find the surface area of the game piece

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