Geometry (calculation)

Hello experts:

My geometry knowledge is a bit rusty... I need some assistance with a calculating a value.

Please see attached XLS which illustrates the shape (and includes the question).

Thank you in advance,
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

You can draw a line parallel to c that goes through the red point.
Once you do that, you will see that any point on the new line could be the red point.

You need more information.  Does the line from c to the red point go through the midpoint of c?  
That would make it easy, because you would have another right triangle.
Thibault St john Cholmondeley-ffeatherstonehaugh the 2ndCommented:
If the red line is perpendicular to the centre of  c then you have enough information. Three pieces of information is enough to find anything on a triangle.
Thibault St john Cholmondeley-ffeatherstonehaugh the 2ndCommented:
I need to type faster:7)
Bootstrap 4: Exploring New Features

Learn how to use and navigate the new features included in Bootstrap 4, the most popular HTML, CSS, and JavaScript framework for developing responsive, mobile-first websites.

ExpExchHelpAnalystAuthor Commented:

When you refer to "mid point of c", I believe you're referring to the center of the red point, correct?   If so, the answer is 'yes'.

ExpExchHelpAnalystAuthor Commented:
Quick follow-up... no, the red point could be anywhere "inside" the triangle.   So, no, it is not always at the mid point of line c.

Guy Hengel [angelIII / a3]Billing EngineerCommented:
it depends on what is known about the angles between "c" and the red line and/or the green line within the angle "ac".
usually a "distance" between a line a point is a perpendicular to the line (and I take that as a premise)
then, the "design" for the green line seems to cut the angle "ac" in half.
as that angle can be determined, you have the length of the red line and the angle opposite to that, so the other 2 lengths can be determined.

hope this helps already
You do have a second right triangle.  The line from the red point to c, is perpendicular to c.  That is what distance means.

You need another piece of information.  
     The distance from the green point to the new right angle would be the easiest.
     Either of the two new angles would work too.
ExpExchHelpAnalystAuthor Commented:
Guy Hengel [angelIII / a3]

The angle between c and red point is 90 degrees.  

Since I don't know the distance from green point to red line (on c), how I can compute the distance of the green line (given that I know the length of the red line)?

You can't, without specifying or measuring something else.

See my first post, and draw the line through the red point.
Any point on that line will satisfy the criteria you have set so far.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
I also see that your drawing is not to scale, the 80 meter side seems to be much longer than the 100 meter side.
How accurate do you need to be.  A proper scale drawing might be all you need.

One way I like to look at the question of whether or not you have enough information is to see if you can "slide" things around and not change any of the knowns.  The only constraints that I read for the red point are that it is inside the triangle and that it is a specified distance away from  the hypotenuse.  You can "slide" that point along the line segment inside the triangle and parallel to the hypotenuse (the black one in d-glitches illustration) and still meet these two conditions.  "Obviously" the distance from the green point to the red point will change.  That says that you don't have enough information to solve this.
ExpExchHelpAnalystAuthor Commented:
All - thank you for your comments.    Need to go back to the drawing board.   Again, I appreciate your assistance.

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Math / Science

From novice to tech pro — start learning today.