To find the surface area, we need to find the area of all the faces of the shape. We find the area of a triangle with the formula 1/2 x base x height. Since we have a base of 4 and a height of 6 we multiply the numbers together and get 24 then divide by 1/2 which gives us 12. Since there are 4 total triangles, we are going to multiply 12 x 4 which gives us 48. The last face of the triangular prism is the bottom which is a square. The area of a square can be found by multiplying length x width which is 4 x 4 = 16. For the final step we add 48 + 16 = 64.