So in the problem, the length of the chord there is the circumference of the tree. So in order to get the diameter of the tree, we must use the formula in getting the circumference of a circle that is stated as follows.
C = 2pi *Radius
so first we need the get the radius of the tree which represent by this formula:
Radius = C /2pi = 8/6.2832 = 1.2732 ft
Diameter = 2*radius = 2 * 1.27 32 = 2.5465 feet
In summary, the diameter of the tree is 2.565 feet.