Question

Find the surface area.

Answer 1

Step-by-step explanation:

a rectangular prism (like this brick) has the same basic structure as a cube (like a die) : it has 6 sides.

while a die has 6 equal sides, a rectangular prism has 3 pairs of equal sides :

top and bottom

left and right

front and back

all we have to do is calculate the areas of the 6 rectangles and add them up. that's it.

your remember, the area of a rectangle is

length × width

in our case we have

top and bottom : 2.5×11.5 × 2 = 28.75×2 = 57.5 in²

left and right : 2.5×5 × 2 = 12.5×2 = 25 in²

front and back : 11.5×5 × 2 = 57.5×2 = 115 in²

so, the total surface area of the whole block is

57.5 + 25 + 115 = 197.5 in²