What is the approximate diameter of the redwood?

felicia is a park ranger, and gives school tours through the redwoods in a national park. someone in ever tour asks, " what is the diameter of the giant redwood tree near the park entrance." felicia knows that the arm span of each student is roughly the same as his or her height. so in response, felicia asks a few students to arrange themselves around the circular base of the tree so that by hugging the tree with arms outstreched they can touch the fingertips to fingertips. she then asks the group to calculate the diameter of the tree. In one group, four students with the heights of 138cm,136cm, 128cm, and 126 cm were able to ring the tree.