• Support PF! Buy your school textbooks, materials and every day products Here!

Perimeter of a triangle which circumscribes by 3 circles

  • #1
Hello, I need help with this problem plz (this is counted as large part of my grade so plz hel) thank you

Problem:
Each of three congruent circles has radius 1, and each is externally tangent to the other two. An equilateral triangle circumsribes this configuration, so that each circle is tangent to two of the sides of the triangle. What is the perimeter of the equilateral triangle?

Here is my diagram. Please excuse me of my badly drawing scale TT

http://www.freeimagehosting.net/uploads/4a1d944fce.jpg
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
25,832
249
Hi Paradiselovek! :smile:

Show us how far you get, and where you're stuck, and then we'll know how to help!

Hint: whenever you see tangent circles, draw the lines connecting their centres! (in this case, making a triangle) :wink:
 
  • #3
Hi Paradiselovek! :smile:

Show us how far you get, and where you're stuck, and then we'll know how to help!

Hint: whenever you see tangent circles, draw the lines connecting their centres! (in this case, making a triangle) :wink:
Well you see, i'm really stuck in this problem. I have no idea where to start to find the perimeter. I'm not asking for step by step but can you please help me by giving hints on those steps?thanks

here what I did like you said:
http://www.freeimagehosting.net/uploads/cccd0e11fa.jpg
 
  • #4
HallsofIvy
Science Advisor
Homework Helper
41,794
925
One thing you can get easily is the perimeter of that inner triangle. Can see what the ratio of "large triangle to small triangle" must be?
 

Related Threads for: Perimeter of a triangle which circumscribes by 3 circles

Replies
5
Views
17K
Replies
6
Views
4K
Replies
1
Views
16K
Replies
34
Views
3K
Replies
2
Views
10K
Replies
5
Views
9K
Replies
10
Views
14K
Top