# TREE-GONOMETERY: Scientific approach to Christmas decorations

### A formula for decorating the perfect Christmas tree has been calculatedby scientists.

The equation uses the size of the tree to calculate the number of baubles, tinsel, necessary lights and the size of the star on top.

It was created by maths students to help those who may have gone overboard on their tree - making it more gaudy than great.

Using their ‘treegonometry’ calculations they say a 5ft (152 cm) tree would need 31 baubles, around 25.5ft (776 cms) of tinsel and 15.7ft (478 cms) of lights with a six inch (15 cm) star or angel to top it off.

They also claim the formula ensures a ‘winter wonderland’ whether it’s a Norwegian Spruce or an artificial model - and works for a tree large enough for the Royal Family at Balmoral or small enough for the most modest of homes.

George Amos, president of Sheffield University’s Maths Society (SUMS), said: “Being interested in maths can be a struggle for a lot of people but this is a brilliant way of showing an applicable side of maths.

“This equation - which was created by two former students and SUMS members a few years ago - is a nice and easy equation to get people involved in maths as well as a bit of good, festive fun.”

The world’s tallest Christmas tree would, at 2,600ft tall, need more than 16,000 baubles, over 13,000ft (4,000 metres) of tinsel, almost 8,200 (2,500 metres) of lights, and a 260ft (80 metre) tall star.

This year’s Trafalgar Square tree is about 25 meters tall, meaning it would need 515 baubles, over 328ft (100 metres) of tinsel, 256ft (78 metres) of lights and an 8ft (2.5 metre) tall star.

The formula is as follows:

Number of baubles = √17÷20 x (tree height in cms)

The length of tinsel (cms) = 13 x π ÷ 8 x (tree height in cms)

The length of lights (cms) = π x (tree height in cms)

The height of the star/fairy (cms) = height of tree (in cms) ÷ 10

But to save time you can visit the university’s website where an online calculator will work out the necessary decorations for whatever size tree you’ve got.

Debenhams, who commissioned the formula, said it allows customers to be savvy when buying Christmas decorations as they can calculate exactly how much they need to create a beautiful tree.