Why is 2,482 not a reasonable answer for 542 times 6

So first off, it's not a reasonable answer because If you round 542 to 500, your estimate would be 500 × 6. Since 500 × 6 = 3,000, then 2,482 would not be a reasonable answer.

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's