What is the surface area of a prism with a length of 15mm a height of 4 mm and a width of 3mm?

Answer 1

The surface area of a prism is twice the area of the end plus the area of all the sides.

For a prism with a polygon cross-section the area of all the sides if given by the perimeter of the cross-section polygon multiplied by the length of the prism.

Assuming you have a prism of cross-section that is a rectangle with sides 4 mm and 3 mm, and is 15 mm long (ie it is an oblong), its surface area is:

→ surface_area = 2 × (4 mm × 3 mm) + 2 × (4 mm + 3 mm) × 15 mm

→ surface area = 2 × 12 mm² + 14 mm × 15 mm = 234 mm²

Answer 2

The answer depends on the cross-sectional area of the prism, not just its height and width.