Newbie- Points on a circle (Biesseworks question)

[cbkrahn]

Hi, my maths have failed me, so I must venture out into the great unknown and ask the internet for help!

Attached is a picture of a circle and a rectangle. The arc formed on the rectangle by the circle is the arc that I wish the rectangle to possess (the circle is for illustrative purposes only). I'm having a problem figuring out how to determine where the points of intersection are.

The centre of the circle is LPX,LPY. The radius is LPX minues the space at the top.

I've been staring at Visual Basic codes and circle math problem online for a couple hours now and am still no closer to an answer than when I began. Hopefully somebody knows more about this stuff than I do!

[KOC62]

Well, if I understand the drawing, you didn't give enough data.

First, the radius doesn't change so it intersects both points on the square. I would draw a line from each point back to your center of the circle. Now you have formed an isosceles triangle. To solve the rest you need enough data, to calculate the points on the triangle formed.

[cbkrahn]

The tangent is the same length as the radius. The height of the triangle formed is, in this case, 127mm (the rectangle is equidistant from the left side, top, and bottom.

Any other data I'm missing?

LPX=2032
LPY=762
Top, Left, and Bottom space =127
Radius=2032-127

[KOC62]

Here is my thinking.
I'm assigning;
Cx = 0
Cy = 0
Lower desired left side point = P1
upper desired left side point = P2

By inspection of your graph;
P1x = LPx -127mm = 1905 mm
P1y = Cy + 127mm

P2y = LPy-127 = 762 - 127 = 641 mm
P2x = Cx + ?

We know P2y, so it forms the "opposite" side of a right angle triangle with the radius forming its hypoteneuse. Then P2x = the "adjacent side of the triangle.
Knowing two sides of a right angle triangle you can calculate the angles so that you can calculate the adjacent line.
I'll leave that as your homework since I didn't go that far.
Or use pythagorean theorem. All the necessary info you now have.

[Kiwi]

Originally Posted by cbkrahn Hi, my maths have failed me, so I must venture out into the great unknown and ask the internet for help!

You asked a math question about step runners over six weeks ago and never looked at the replies. Why should anyone bother to answer your questions?

[cbkrahn]

Originally Posted by Kiwi You asked a math question about step runners over six weeks ago and never looked at the replies. Why should anyone bother to answer your questions?

Dude, my question was answered and the problem solved. I was able to work it out in part from the information you gave me too. Apologies for not saying 'thanks', but I don't get paid to surf forums.

[holbieone]

Trig. It out , solve for a right triangle

[cbkrahn]

When the boss said to learn how to use a CNC, he didn't inform me I needed trig.

Anyways, after 2 hours of trying every combination of trig I could come up with, none of it works. I used the ATN function and the pythagoream theory and neither of them seemed to work. After about 2 hours I took a line with the length of my radius and ran it from my origin point, only to discover that Biesseworks was drawing the circle I was using as a reference wrong. So I lost 2 hours to a rendering error.

Ah well, learning every minute. Works fine now!

[Kiwi]

Originally Posted by cbkrahn ... but I don't get paid to surf forums.

Jerk..Members who answer questions don't get paid for their time either. Looks like your getting paid for a job that you can't handle.