Dave is comparing the circumferences of several trees in his yard. The oak tree is 0.539 meters in circumference, the ash tree has a circumference of 0.509 yards, the elm tree is 6281.70 millimeters around, and the poplar has a circumference of 0.000385 miles. There are 30.48 centimeters in a foot. Which tree has the greatest circumference?

Convert the circumferences to centimeters to compare them. The elm measures 6281.70 millimeters, which is 628.17 centimeters. The other trees are smaller: the oak is 53.9 cm, the ash is about 46.54 cm, and the poplar is about 61.96 cm (using 30.48 cm per foot). Therefore, the elm tree has the greatest circumference.

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