You can put this solution on YOUR website! Climb to the top of the tree, using the ruler to measure as you ascend.
When you're back on the ground, put the ruler in the pie pan to carry it home.
You can put this solution on YOUR website! Measure the pan's diameter, find out the height of the tree (by measuring) in pans (the amount of pans the height of the tree is equivilant to). Then convert this into inches, feet, yards, whatever your ruler used as a measurement knowing the diameter of the pan.