Question

surface area and volume​

Answer 1

Answer:

area of cuboid = 2(l+b×b+h×h+l)

by putting the values

we find that

area=717.50

note first convert cm to m

Answer 2

Given

• Length of box(l) = 1.5m
• Breadth of box(b) = 1.25m
• Height of box(h) = 0.65 m

Used Formula

• Surface area of cuboid(box) = 2(lb+bh+hl)

Solution

☛ Detemine the area of sheet required for making box?

Since, the box is open at the top, it has only 5 faces.

So,

$\tt Surface \: area \: of \: box \: = lb + 2(bh + hl) \\ \tt \implies = 1.5 × 1.25 + 2 (1.25 × 0.65 + 0.65 × 1.5) m {}^{2} \\ \tt \implies = 1.875 + 2 (1.7875) m {}^{2} \\ \tt \implies = (1.875 + 3.575) m {}^{2}$

$\large \implies {\boxed {\tt \green {= 5.45 m {}^{2} }}}$

☛ The cost of sheet for it, if a sheet measuring 1 m2 costs Rs 20.

$\tt Cost \: of \: 1m {}^{2} \: of \: the \: sheet = Rs20 \\ \tt Cost \: of \: 5.45m {}^{2} \: of \: the \: sheet = 20 \times 5.45m {}^{2}$

$\large \implies {\boxed {\tt \green {=Rs.109 }}}$