Quandaries
and Queries 

Scott I am a parent. The level of the question secondary (1012) I want to build a octagonal deck. The wood I am using are cut in 8 foot lenghts. What I want to know is if the sides of the octagonal are 8 feet, what is the diameter. Also what are the angles of each side? Your help is greatly appreciatted. 

Hi Scott, From the diagram you can see that d = 8 + 2x feet, where d is the diameter.
Thus if you can find x then d is easy to calculate. Triangle ABC is a right triangle, so by Pythagoras' Theorem
Thus
Thus
Thus
which is approximately 19 feet 3 ^{3}/_{4} inches. The angle calculation you can find in the answer to a previous question. Penny 

