2 sides of a triangle must equal to more than the last side of the triangle. So, 6 + 15 is more than 6 cm, also more than 8 cm, and also more than 18 cm. So the answer must be 21 cm. I hope this helped and please mark me brainliest!
Thousand is 1,000, or 10^3, when multiplied by the 100 in 427, it becomes 10^5. Because we divided 427 and put the notation in the 10^#. It would be 4.27, once we add the ten^#, it becomes..
