This is a triangular prism, the ground is a right triangle, the two right-angled sides of the triangle are 3 and 4, and the height of the triangular prism is 15.

Then the length of the side = the perimeter of two triangles+the height of three triangles =(3+4+5)*2+3* 15=69.

The surface area is 2 * 3 * 4/2+(3+4+5) *15 =102.