Drawing a circle whose edges are tangent to a Line and the curve of a large Circle

[peterg7X5LU]

Hello,

As the title suggests, I need to draw a small circle within a much large circle whose edges are tangent to a vertical line (shown in the picture below), and also to the edge of the much larger circle (the large curve in the picture below).

I have tried drawing the circle using 2 points or 3 points, and then connecting it to the lines by using the tangent function, but the larger circle moves to the smaller circle, not vice versa which is what I want.  How do I achieve this please?  I need the vertical line and the large outer circle to stay the same position, and the small circle (one of edge of which is already tangent at the top) to be the one that moves its position to get to the line tangent.

[wmhazzard]

You need to fully constrain the large circle and line in order to "keep them in place". Dimension the circle and line along with dimensions and or constraints to the origin. Then dimension the small circles but you don't have to do it in that order though. Once you get the sketch fully constrained (blue lines turned black) everything should be where you want it. 

[jhackney1972 · Accepted solution]

You need to add sketch constrains to the large circle and line first, then the small circle can be placed using two tangent sketch constraints and a dimension.

[peterg7X5LU]

This works, thanks very much, it's always appreciated. Same for the other poster too.