You and your cousin are walking through the lunchroom when you both trip. Your trays hit the ground and both lunches fly through the air in parabolic paths until they hit your friend on the top of the head. If your lunches had not landed on your friend's head, then your hamburger would have landed on the floor 12 feet away and your cousin's chili would have landed 16 feet away. Your hamburger reaches a height of 13 feet and your cousin's chili reaches a height of 6 feet. How tall is your friend? Explain.