Question

the volume of a cuboid is 80 cm cube and length and breadth are 5 and 2 cm find total surface area and length of diagonal of cuboid ​

Answer 1

volume of cuboid =lbh

$80 = 5 \times 2 \times h \\ 80 = 10 \times h \\ 80 \div 10 = h \\ 8 = h$

total surface area=2(lb+bh+hl)

$= 2(5 \times 2 + 2 \times 8 + 8 \times 5) \\ = 2(10 + 16 + 40) \\ \\ = 2(66) \\ = 132$

length of diagonal=?
In ΔABC
angle B=90°
by pythagoras theorem
length ^+breadth^=diagonal^
5^+2^=diagonal^
25+4=diagonal^
29=diagonal^
taking square root
diagonal=√29