# The radius of a circle inscribed in 2 triangles

1. Apr 14, 2015

### eXmag

Hi guys, was wondering if anyone could help me solve this problem. Thanks!

2. Apr 14, 2015

### Delta²

Have you been taught the concept of similarity of triangles and/or pythagorean theorem or the definition of trigonometric functions? In any case you should show us any attempts you ve made.

3. Apr 14, 2015

### mathman

It looks trivial. cos(x)=B/E, sin(x)=r/B. $(r/B)^2+(B/E)^2=1,r=B\sqrt{1-(B/E)^2}$

4. Apr 14, 2015

### Staff: Mentor

Homework in the wrong forum and without the template or attempts at work done should be reported only.

5. Apr 14, 2015

### eXmag

This isn't school homework which is why I didn't post it here in the first place. Its a problem that I've encountered and was asking for help as I have no idea how to solve it. That's it.

6. Apr 14, 2015

### eXmag

Thanks for your help mathman, your reply is all I was looking for.

7. Apr 15, 2015

### BruceW

you can do this problem by thinking about similar triangles. Have a go at it, think for a bit about the angles of various triangles. If two triangles contain the same angles, then they are similar.