Question

Q find the side of a cube of its total surface area is 486 cm square?

Answer 1

Hi ,

Let side length of the cube = a cm

We know that
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Total surface area of the cube = 6a ^2

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Given

Total surface area of the cube = 486

Square cm

6a ^2 = 486

a^2 = 486/6

After cancellation

a^2 = 81

a = + or - sqrt(81)

a = 9 or -9

But side length should not negative.

Therefore

Side length of the cube = a = 9cm

I hope this will usful you.

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Answer 2

Let the Total Surface Area be x cm

According to Question,

Total surface area = 486 cm²

⇒ 6 × x² = 486
⇒ 6x² = 486
⇒ x² = 486 / 6
⇒ x² = 81
⇒ x = √81
⇒ x = 9

Hence, the side is 9 cm.

Hope it helps ツ