# Thread: difficult algebraic expressions to characterise a simple triangle

1. ## difficult algebraic expressions to characterise a simple triangle

Hello

The k's are known, I want to deduce A. For the moment I'm using the formula linking the 3 sides to the cosinus of an angle. I try varying values of A till I find a value for the angle k4 which coincides with its known vale. Maybe you can find a 'cleaner' solution. Thanks

2. ## Re: difficult algebraic expressions to characterise a simple triangle

Yes, this is really good and simple.
You have any these type simple solutions please provide
Thank you
Bizworldusa

3. ## Re: difficult algebraic expressions to characterise a simple triangle

Originally Posted by Roger44
Hello

The k's are known, I want to deduce A. For the moment I'm using the formula linking the 3 sides to the cosinus of an angle. I try varying values of A till I find a value for the angle k4 which coincides with its known vale. Maybe you can find a 'cleaner' solution. Thanks

I'm a little confused about the diagram. Are the k's angles or are they distances? Specifically k4 seems to be an angle, but k3 is then added to A^2, which is a distance^2. And k2 isn't even mentioned. If they are simply mathematical numbers (no units) then you are going to have to specify the type of angle measure (degrees, radians, etc.)

My best guess is that we don't have enough information to solve this.

-Dan

4. ## Re: difficult algebraic expressions to characterise a simple triangle

k4 is an angle whose numerical value we know.
k3 is the square of a length whose value we know
k1 is the reciprical of cos k4, so just another numerical value we know
k2 (he's there) is a known length divided by the sinus of a known angle, so just another numerical value we know.

I've looked at the link to the polynomial approach, I can't quite see how to get round the fact that I have an A and the square root of A+constant.