# Need to figure distance between two points/lines.

I am trying to figure out how to figure out distances between lines on a graph. And how to do it on a ti 84 or whatever is easiest and translate that to real world dimensions. And have a program for it so I can plug in different numbers for different scenarios. The first line is a straight line 300 feet long between two points with different elevations. The second line has different elevations along it, say every 10 feet but it would be nice to be able to change this distance. The second line should be within 7.5 tenths of the first line. It may not be and so I will have to change it for my application. I just need to be able to see where it is now.

An example. The first line starts at elevation 100 and ends at elevation 105. A point in the middle of this line at 150 feet would obviously be 102.5. The second line in the middle at 150 feet has an elevation of 103.5. This point is 2.5 tenths of a foot too high and will need to be changed to 103.25 to be within spec.

A second example would be on the second line 10 feet in, it is 3 tenths below the first line but 200 feet in, it is 6 tenths above the first line. This is 1.5 tenths out of spec and one of the points will need to be changed. If the both of the elevations on the end points of the first line were 100, this would be easy to check. Alas, its not always like this. What do I need to google to figure this out or what formula do I need to use? It would be great if I could quickly plug in my numbers and calculate it as I have dozens and dozens to do. Thanks.

Edit:Perhaps it would help if I outlined the actual scenario I am doing. This is for building a 3d model for the dirtwork on a solar farm. Each array of solar panels is sitting on piles driven into the ground. Each array is 300 feet long with piles every 24 feet. The piles have 7.5 tenths of tolerance to adjust for the ground. The engineers have given us a model that has problem areas. The picture I posted has a straight line from elevation 601 to 607. The other line with curves is an example of the natural ground that the piles will be driven into and which may need to be changed in relation to the first line. This is a profile view.

https://flic.kr/p/2n4Dr5N
• Nirenberg

Your question is a bit vague. What do you mean by a line starting at elevation 100? The y-coordinates is 100? What is the x-coordinate of the point? In the attached email you have a straight line and a curve, not two line. It would help if you just draw a careful picture for one of the scenarios you mentioned above. Add a Comment

• Jordylee18

Perhaps it would help if I outlined the actual scenario I am doing. This is for building a 3d model for the dirtwork on a solar farm. Each array of solar panels is sitting on piles driven into the ground. Each array is 300 feet long with piles every 24 feet. The piles have 7.5 tenths of tolerance to adjust for the ground. The engineers have given us a model that has problem areas. I am trying to fix them. I will post a second picture for the first example.

• Jordylee18

I dont know how to change the picture. It won't let me when I try to edit it.

• Nirenberg

Yes, I good picture with detailed information on it would help me understand the problem.

• Nirenberg

• Jordylee18

Put a Flickr link in my last edit, Philip.

• Nirenberg

The picture is very clear now. Could you please clarify what is the unknown that you want to compute in the attached picture?

• Nirenberg

Is the unknown what you call "Distance apart " in your picture?

• Jordylee18

Yes thats correct. I need to be able to figure the distance apart on on several points between line 1 and 2 quickly and easily to make sure their average from line 1 is never more than 7.5 tenths. For instance, line 2 may be 3 tenths below line 1 20 feet from start but 6 tenths above it 200 feet from the start of line one. This would need to be fixed.

• Alessandro Iraci

Wait, so you know the horizontal distance and need to compute the vertical one? I feel like it would be very easy to answer the question, but I don't understand exactly what you mean.

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