N 8
we have that
The volume of the door is
V=L*W*H
we have
H=80 in
L=36 in
W=2 in
substitute given values
V=36*2*80
V=5,760 in3
N 10
The area of a rectangle (living room) is equal to
A=L*W
we have
A=224 ft2
W=14 ft
substitute given values
224=L*14
solve for L
L=224/14
L=16 ft