Question

Two circles are adjacent as follow.
https://dl.dropbox.com/u/63664351/Circle%20Adjacent.PNG
If the diameter of a smaller circle is \(a\) and the diameter of larger circle is \(b\), find the length of all sides of the quadrangle.

Answer 1

see 1 side will be radius of larger circle means b/2 opposite to that will be radius of smaller side means a/2. in between side of these will be sum of radius of larger and smaller circles = a/2 + b/2 . last side try to find by yourself using pythagoras

Answer 2

I don't know how to find the one side which is also a common tangent of the circles. How can I apply Pythagoras here?

Answer 3

draw a line parallel to the tangent from the centre of the smaller circle
and then you will get a right angled triangle and use pythagoras

Answer 4

I don't see how that is helping me.

Answer 5

now use pythagoras

Answer 6

So those both x are the same?

Answer 7

yup this quadrilateral becomes a rectangle as all angles are 90 degrees

Answer 8

let say the radius of smaller circle is 4 and radius of larger circle is 9. What is the common tangent?

Answer 9

sorry a mistake in the figure i will correct it