Total surface area of a cube is 864 sq.cm. Find its volume.

1.	Total surface area of a cube is 864 sq.cm. Find its volume.
Answer» Given: Total surface area of cube = 864 sq. cm To find: Volume of cube Solution: i. Total surface area of cube = 6l² ∴ 864 = 6l² ∴ l² = \(\sqrt[864]6\) ∴ l² = 144 ∴ l = \(\sqrt{144}\)… [Taking square root on both sides] = 12 cm ii. Volume of cube = l² = 12³ = 1728 cubic cm. ∴ The volume of cube is 1728 cubic cm.

Answer»

Given: Total surface area of cube = 864 sq. cm

To find: Volume of cube

Solution:

i. Total surface area of cube = 6l²

∴ 864 = 6l²

∴ l² = \(\sqrt[864]6\)

∴ l² = 144

∴ l = \(\sqrt{144}\)… [Taking square root on both sides]

= 12 cm

ii. Volume of cube = l²

= 12³

= 1728 cubic cm.

∴ The volume of cube is 1728 cubic cm.

Discussion