Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.

Hi all,

Can someone help me with this problem about convex quadrilaterals:

Consider a convex quadrilateral ABCD as in this figure:

In my problem known are: The two opposite sides AB and CD, the two diagonals AC and BD and the angle of sides AB and CD (in figure angle DPA).
What are the lengths of the sides AD and BC as a function of the above parameters?

MechDB
MechDB

Posts: 2
Joined: Thu Apr 04, 2013 9:54 am

You have posted this exercise to many different places, but haven't yet shown any work.

Typically, one needs a certain number of independent facts about a figure in order to "solve" it. Do you have enough facts for this figure?

stapel_eliz

Posts: 1797
Joined: Mon Dec 08, 2008 4:22 pm

### Re: Quadrilateral Problem

Thanks for your reply. As is mentioned in a different topic I need 5 facts to solve it, which makes this problem solvable.

I used a different approach in solving this problem, by chosing a input variable <ABD instead of <DPA. Using laws of cosines I calculated AD and <QAD and <DAB. This allows me to calculate length CD as well.
MechDB

Posts: 2
Joined: Thu Apr 04, 2013 9:54 am