The longest diagonal of a cube is 6$$\sqrt{\smash[b]{3}}$$​ cm. Find the total surface area of the cube.

Correct option is B

Diagonal of a cube =  6$$\sqrt{\smash[b]{3}}$$​ cm

Side $$\sqrt{\smash[b]{3}}$$​ = 6$$\sqrt{\smash[b]{3}}$$​ cm

Side = 6 cm

Total Surface Area = 6$$(Side)^2$$​ = 6 × 36= 216 $$cm^2$$​​