Each of the four outside walls of the large wooden box shown above is to be covered with waterproof plastic that comes in 3-foot-wide rolls. The plastic does not overlap. What is the total length, in feet, of plastic, needed to cover the four walls?

A) 21 ft
B) 42 ft
C) 63 ft
D) 84 ft
E) 126 ft

Explain too, thanks.

Each of the four outside walls of the large wooden box shown above is to be covered with waterproof plastic that comes in 3footwide rolls The plastic does not o class=

Respuesta :

we need the lateral aera
that will be
LA=2H(L+W)

H=6
L=12
W=9
LA=2(6)(12+9)
LA=12(21)
LA=252

so we need 252 square feet
it comes in 3ft width so
3ft times ?=252
divide both sides by 3ft
?=84

we need 84ft of that wrap

D is answer