Can't find circle centre

Hi,

Can someone tell me how to find the centre for the circle R23 on the attachment as it is not on the same plane as the opposite R30.

Also do I draw the polylines and then round of using fillet for radius or is there a better way.

Any advice greatly appreciated

Mark..

Draw a horizontal line, this will represent the straight part at the top of your figure. Draw a perpendicular line down from that line, the center of the R30 will be on this line. Copy this perpendicular line to the left by the dimension shown, the center for the R23 will be on this line.

I'm sure that you just have a mental block on this one - as you start to draw it, things will become clear. My personal preference is to use lines and circles, then trim where necessary and PEDIT everything together at the end, but others may do it differently.

Good luck, and post your progress.

Glen

Hi Glen,

Thanks for the reply,the R23 radius dosent seem to be on the same centre line as the R30.

Thanks...

manich1: You're right...it isn't. It's 23 units offset from the horizontal line at the top and 73 units offset from the centerline of the R30 radius. Just follow Glen's advice.

Very down and dirty....

The center line for the R30 will be 30 units down from the horizontal line on the right vertical line. The center line for the R23 will be 23 units down from the Horizontal line. If the radius was 5 the center line would be 5 units down. Therefore the center line for the R23 would be 30 - 23 = 7 units up from the R30.

Very rarely will a needed dimension be missing entirely from your assignment. You simply need to look at the figure as a whole and see if you can get the information from some other part of it. In this case, you know the circles are tangent to the horizontal line we started with, and therefore the center lines are one radius distant from that line.

Good luck.

Glen

Ah I see,Thanks guys

Mark

when i cnt find a centre of a circle, i just hold shift and right click then press centre on the menu. but maybe this doesnt help your case. Hope you fixed it.

Finding the center of an existing circle and resconstructing the location for the center of a circle are two different things aren't they?

Yes, but I still like the old stand-by manual method:

The perpendicular bisector of any two non-parallel chords will intersect at the center of the circle.

However this one was easily resolved by viewing the radius of 30 vs 23. The horizontal dimension between the centers would be 7 units.

Bill: The circle in question has not been drawn yet. The OP is trying to locate the center so he can draw his circle. Be that as it may your advice is as sound as rock.