Answer:[tex]8746.65\ m^2[/tex]
Step-by-step explanation:
Given
Base of mail box is [tex]0.4\ m\times 0.7\ m[/tex]
height of mail box [tex]h=0.55\ m[/tex]
Total area required for one mail box
[tex]A_t=\text{surface area of cubiod} - \text{Top of cubiod +Semi-cylinder area}[/tex]
[tex]A_t=2(lb+bh+hl)-lb+\pi rh'[/tex]
where [tex]b=0.4\ m[/tex]
[tex]l=0.7\ m[/tex]
[tex]h=0.55\ m[/tex]
[tex]r=\frac{0.4}{2}=0.2\ m[/tex]
[tex]h'=0.7\ m[/tex]
Substituting values
[tex]A_t=2(0.7\times 0.4+0.4\times 0.55+0.55\times 0.7)-0.4\times 0.7+\pi \times 0.2\times 0.7[/tex]
[tex]A_t=2(0.28+0.385+0.22)-0.28+\pi \times 0.14[/tex]
[tex]A_t=1.77-0.28+4.4[/tex]
[tex]A_t=5.89\ m^2[/tex]
Therefore for 1485 mailboxes Area required
[tex]A_o=1485\times 5.89=8746.65\ m^2[/tex]