# Thread: Distance between center of two circles

1. ## Distance between center of two circles

I have to find O1O2 but I've no idea how.. Any advices ? Thank you!

2. ## Re: Distance between center of two circles

This is not a homework service.
That is not the way it works here. You must show some effort. Post some effort.
Then then tell us what you do not understand.

3. ## Re: Distance between center of two circles

Hello, jamiee!

I have to find O1O2.

You know you have a trapezoid, don't you?
Take a good look at it.

Code:
    O1*
| *
|   *
8 |     *
|       *
|         *
* . . . . . *O2
|    15     |
3 |           | 3
|           |
* - - - - - *
15
Do you see the right triangle?

4. ## Re: Distance between center of two circles

If you draw a line from $O_2$ perpendicular to $AO_1$ you cut the figure into a rectangle and a right triangle (the right triangle Soroban is referring to). The distance between centers is the length of the hypotenuse of that right triangle. What are the lengths of the two legs of the right triangle?