I'm not sure how to do this problem

[Xearf_987]

What is the radius of a circle inscribed in a 9-12-15 triangle? Please help!

 

[zerodegrees]

Well, the triangle is a right triangle. Does that help?

 

[tkhunny]

What is the radius of a circle inscribed in a 9-12-15 triangle? Please help!

That's a very interesting question. You should have some fun with it. Start here...http://www.saltire.com/applets/pythag/incircle.html