# Find intersection points of lines using ListPlot?

**URL:** <https://community.wolfram.com/t/find-intersection-points-of-lines-using-listplot/11653>\
**Category:** Questions\
**Tags:** equation-solving, graphics-and-visualization\
**Created:** [December 8, 2017, 6:27pm UTC](https://community.wolfram.com/t/find-intersection-points-of-lines-using-listplot/11653 "2017-12-08T18:27:16Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![anon\_91240867](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anon\_91240867](https://community.wolfram.com/u/anon_91240867)\
**Post date:** [December 8, 2017, 6:27pm UTC](https://community.wolfram.com/t/find-intersection-points-of-lines-using-listplot/11653/1 "2017-12-08T18:27:16Z")

</div>

Hello, I am trying to find the intersection points of the two horizontal solid lined with the dashed line. I would like to label each point as for example point a and the second point as b. I would also like to display the value of the intersecting point. Note that I am aiming to find the x value of the intersecting point since I know y. I find it easier with function and using Plot function. I tried with this one but it didn’t work.  
Thank you

```
list1 = {0, 1};
list2 = {0, 5};
ListLinePlot[Transpose[{list1, list2}], PlotStyle -> {Thick, Dashed}, 
 PlotRange -> {{0, 5}, {0, 5}}, 
 GridLines -> {None, {{2, {Black, Thick}}, {4, {Green, Thick}}}}]

```

---

<div class="post-metadata">

**Author:** ![josklaps1](https://yyz1.discourse-cdn.com/wolfram/user_avatar/community.wolfram.com/josklaps1/32/22044_2.png) [@josklaps1](https://community.wolfram.com/u/josklaps1)\
**Post date:** [December 10, 2017, 2:56pm UTC](https://community.wolfram.com/t/find-intersection-points-of-lines-using-listplot/11653/2 "2017-12-10T14:56:22Z")

</div>

Hi Joseph,

I hope this will help !

```
list1 = {0, 1};
list2 = {0, 5};
ListLinePlot[Transpose[{list1, list2}]
 , plot = PlotStyle -> {Thick, Dashed}
 , PlotRange -> {{0, 5}, {0, 5}}
 , GridLines -> {None, {{2, {Black, Thick}}, {4, {Green, Thick}}}}
 , Mesh -> {{2, 4}}
 , MeshFunctions -> {#2 &}
 , MeshStyle -> Directive[Red, PointSize[0.03]]
 ]

```

 ![test1.jpg](https://global.discourse-cdn.com/wolfram/original/3X/a/1/a1bc665ad63af625f54b7bda60f153268cca8b78.jpeg)

```
lst1 = Table[i, {i, {2, 2, 2, 2, 2}}];
lst2 = Table[i, {i, {4, 4, 4, 4, 4}}];
lst3 = Table[x, {x, {0, 5}}];
plot = ListLinePlot[{lst1, lst2, lst3}
  , PlotRange -> {{1, 5}, {0, 5}}
  ]
a = Graphics`Mesh`FindIntersections@plot
Length[a]

```

 ![test3.jpg](https://global.discourse-cdn.com/wolfram/original/3X/7/2/7295fcc5e357f336ec31d9b84020b17b1f0273f7.jpeg)

Regards,…Jos

---

<div class="post-metadata">

**Author:** ![anon\_91240867](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@anon\_91240867](https://community.wolfram.com/u/anon_91240867)\
**Post date:** [December 12, 2017, 7:32pm UTC](https://community.wolfram.com/t/find-intersection-points-of-lines-using-listplot/11653/3 "2017-12-12T19:32:55Z")

</div>

That was very helpful. Thank you Jos