Question

If the surface area of cube is 486cm².find the length of the diagonal.

Answer 1

we have given that :
volume of a cube is 729 cm³

we have to find :-
surface area and the length of a diagonal = ?

solution :-
we know that :
volume of cube = a³
surface area of cube = 6a²
and
length of diagonal = a√3

here,
a³ = 729 cm³
=> a³ = 9³ cm³
=> a = 9 cm

now
surface area = 6 a² = 6×9²
= 6 × 81 = 486 cm²

and
length of diagonal =a √3 = 9 ×√3 cm

✰✰ hope it helps ✰✰