Question

The length of the diagonal of a cube is √243 cm its total surface area is

Answer 1

here is the formula to determine the diagonal of a cube i.e .
diagonal of a cube=(rootover 3)×a
where ,a=side of a diagonal
$\sqrt{243 } = \sqrt{3 \times 3 \times 3 \times 3 \times 3} \\ \: =9 \sqrt{3}$
so,
$\sqrt{3} a = 9 \sqrt{3 }$
hence a=9

its total surface area=6a^2
=6×9^2
=6×81
=486