Perimeter of a triangle which circumscribes by 3 circles

In summary, the problem involves three congruent circles with radius 1 that are externally tangent to each other. An equilateral triangle circumscribes this configuration, with each circle tangent to two sides of the triangle. The task is to find the perimeter of the equilateral triangle. By drawing the lines connecting the centers of the tangent circles, we can see that the perimeter of the inner triangle is easily obtainable. The ratio of the perimeter of the larger triangle to the smaller triangle can also be determined.
  • #1
Paradiselovek
9
0
Hello, I need help with this problem please (this is counted as large part of my grade so please 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
 
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  • #2
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
tiny-tim said:
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
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 to Perimeter of a triangle which circumscribes by 3 circles

1. What is the formula for finding the perimeter of a triangle circumscribed by 3 circles?

The formula for finding the perimeter of a triangle circumscribed by 3 circles is P = 2πr, where P is the perimeter and r is the radius of the circles.

2. How do you know if a triangle is circumscribed by 3 circles?

A triangle is circumscribed by 3 circles if all 3 circles intersect at exactly one point, known as the circumcenter of the triangle. This can be determined by drawing the circles and checking for the intersecting point.

3. Can a triangle have more than one circle circumscribing it?

No, a triangle can only have one circle circumscribing it. This is because the radius of the circle and the distance between the center of the circle and the vertices of the triangle are fixed, making it impossible for more than one circle to fit perfectly around the triangle.

4. How does the size of the circles affect the perimeter of the circumscribed triangle?

The size of the circles does not affect the perimeter of the circumscribed triangle. The perimeter is solely determined by the radius of the circles, not their size.

5. What is the significance of a triangle being circumscribed by 3 circles?

A triangle circumscribed by 3 circles has a unique property where the perpendicular bisectors of its sides all intersect at the same point, known as the circumcenter. This point is equidistant from the vertices of the triangle and has various applications in geometry and trigonometry problems.

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