# Treegonometry uses math to perfectly decorate a Christmas tree

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Picked by Techconnect's Editors Mike the Intern tries his hand at Treegonometry. We're not mathematicians, but we're pretty sure that we're doing this wrong. Read on for the real formulas.

Decorating the tree by committee is probably the worst thing about Christmas. Tinsel or no tinsel, how many ornaments there should be, why not just set the tree on fire if you want to make it so bright, and so on.

Instead of arguing this year, why not use the universal laws of mathematics? Mathematicians from Great Britain’s University of Sheffield have developed a formula to perfectly decorate any Christmas tree called Treegonometry (groan).

Sheffield students Nicole Wrightham and Alex Craig created the formula to perfectly decorate a tree as part of a challenge put out by the Debenhams department store. The calculations will tell you exactly how many meters of lights and how much tinsel you should use, as well as the height of the angel or star that should go on top of the tree.

The formulas are as follows:

• Number of baubles: Take the square root of 17, divide it by 20 and multiply it by the height of tree (in centimetres).
• Length of tinsel: 13 multiplied by Pi (3.1415) divided by 8, then multiplied by tree height.
• Length of tree lights: Pi multiplied by tree height
• Height (in centimetres) of star or fairy on top of tree: Tree height divided by 10.

If you want to skip the math, the pair of students also put out a calculator that will compute it all for you simply by the tree’s height. For example, a tree that's 140 centimeters (55 inches) tall would need 29 baubles, 715 centimeters (281.5 inches) of tinsel, 440 centimeters (173.2 inches) of lights, and a 14-centimeter (5.5-inch) decoration on top.

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