the height of the box is 9 inches
Answer:
solution given:
total surface area of a box=160 square inches
let length, width, and height be l,b, and h respectively.
according to the question:
l=2b
∴b =[tex]\frac{l}{2}[/tex]
l=h-4
∴ h=l+4
we have
total surface area of a box=160 square inches
2(lb+lh+bh)=160
[tex]2(l*\frac{l}{2}+l(l+4)+\frac{l}{2}*(l+4))=160[/tex]
[tex]2*\frac{l^2+2l^2+8l+l^2+4l}{2}=160[/tex]
[tex]4l^2+12l=160[/tex]
[tex]4(l^2+3l)=160[/tex]
[tex]l^2+3l=\frac{160}{4}[/tex]
[tex]l^2+3l-40=0[/tex]
doing middle term factorization
[tex]l^2+(8-5}l-40=0[/tex]
[tex]l^2+8l-5l-40=0[/tex]
taking common from each two terms
l(l+8)-5(l+8)=0
(l+8)(l-5)=0
either
l=-8[neglected as length is always positive]
or
l=5
now
b=[tex]\frac{5}{2} =2.5[/tex]
h=5+4=9
Step-by-step explanation:
