# How to solve this problem?
**URL:** https://boards.straightdope.com/t/how-to-solve-this-problem/640732
**Category:** Factual Questions
**Created:** [November 12, 2012, 12:11am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732 "2012-11-12T00:11:15Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@R3d\_Anonymous](https://boards.straightdope.com/u/R3d_Anonymous)
#### Post date: [November 12, 2012, 12:11am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/1 "2012-11-12T00:11:15Z")
I forgot to ask my mathematics teacher for help on this problem and I can’t figure it out:
Here’s the link (you are supposed to find _x_\*\*:
[http://acr.kendallhunt.com/KeyPressPortalV5.0/ImportingCourses2/DG/images/589\_img\_9.gif](http://acr.kendallhunt.com/KeyPressPortalV5.0/ImportingCourses2/DG/images/589_img_9.gif)
---
### Author:  [@R3d\_Anonymous](https://boards.straightdope.com/u/R3d_Anonymous)
#### Post date: [November 12, 2012, 12:17am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/2 "2012-11-12T00:17:12Z")
Oh never mind. I know how to do it now!
---
### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [November 12, 2012, 5:33am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/3 "2012-11-12T05:33:28Z")
Glad we could help.
---
### Author:  [@RadicalPi](https://boards.straightdope.com/u/RadicalPi)
#### Post date: [November 12, 2012, 7:05am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/4 "2012-11-12T07:05:34Z")
I get _x_ = 6.
---
### Author:  [@SayTwo](https://boards.straightdope.com/u/SayTwo)
#### Post date: [November 12, 2012, 7:18am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/5 "2012-11-12T07:18:42Z")
I can’t see the theta’s, in the image.
---
### Author:  [@Aspidistra](https://boards.straightdope.com/u/Aspidistra)
#### Post date: [November 12, 2012, 8:28am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/6 "2012-11-12T08:28:01Z")
You know the saying. In order to solve any problem you need two people, one of whom need know nothing about it. 😉
---
### Author:  [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)
#### Post date: [November 12, 2012, 8:37am UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/7 "2012-11-12T08:37:31Z")
It’s easy to do with trig, but that’s probably cheating.
The more geometric way:
Call the points of the large triangle A, B, and C going clockwise from the top. Call the point to the left of line segment x point D, and the one to the right E.
First, note that angle DEC is the same as the marked angles to to the parallel line rule. Then, triangle DEC is isosceles and line segments DE (also called x) and CD are the same length.
Triangle AED is similar to triangle ABC, so the line segments they’re made from must also be similar. Therefore, 15/(AD) = 10/x, or 15x = 10(AD). We also have (AD) + x = 15, or (AD) = 15 - x.
Substituting, we have 15x = 10(15 - x), or 15x = 150 - 10x, or 25x = 150, or x = 6. QED, or something.
---
### Author:  [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)
#### Post date: [November 12, 2012, 1:57pm UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/8 "2012-11-12T13:57:08Z")
> [@Anonymous User](#):
>
> Here’s the link (you are supposed to find _x_\*\*:
I found it! There it is!
---
### Author:  [@AskNott](https://boards.straightdope.com/u/AskNott)
#### Post date: [November 12, 2012, 9:48pm UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/9 "2012-11-12T21:48:46Z")
The son of the squaw on the hippopotamus is equal to…
Aw, never mind.
---
### Author:  [@standingwave](https://boards.straightdope.com/u/standingwave)
#### Post date: [November 12, 2012, 10:58pm UTC](https://boards.straightdope.com/t/how-to-solve-this-problem/640732/10 "2012-11-12T22:58:58Z")
> [@Thudlow\_Boink](#):
>
> I found it! There it is!
Me too!
[http://i45.tinypic.com/f432ol.gif](http://i45.tinypic.com/f432ol.gif)