Plz help me I am stuck in this stupid competition math class nobody wants to be in and I must solve problems that use theorems we never learned and if we don't she yells at us and says we should google it or call a friend.
Your question was automatically flagged because of the language that you used. It is not helpful in life to go around calling everything that you find difficult 'stupid'. The only think that it brings into question is your own intelligence.
Anyway I have unflagged it and will answer I hope you learn more from my answer than just how to cheat with minimum effort.
A proper thank you or polite feedback will be appreciated.
I will do a pictorial answer. There may be an easier way but then again the problem was not supposed to be easy.
I will also do it over several posts as I have found that too many pics in one post causes problems.
You should be able to follow but if you have specific question on specific diagrams feel free to ask.
Firstly you should sketch this and realize immediately that ABCD is a kite. You should also already know that the diagonals of a kite bisect each other at right angles.
now use cosine formula to finish it.
I have done it and was going to present my answer but since it is a comptetition I should leave some for you to do.
Hint: there is a square root in the answer.
Have fun :)
There is a problem with the image viewer at present.
If you cannot see the images then follow the instructions(by CPhill and Hectictar) here
This post is also the first one in the 'sticky topics' so that it can be easily found.