How do I close this drawing?

[prime333]

Seems to be pretty easy, but I don't know how to close it off as I don't know how to locate that last point. Radius is 65(hard to see)

key hole.dwg

[JD Mather]

 

Here is a hint.

[ReMark]

And another: Circle > Ttr

[prime333]

[ATTACH=CONFIG]48422[/ATTACH]

 

Here is a hint.

 

 

 

I see the center of the blue circle is where two red circle meet. Though how do you come up with the 2 red circles?

[ReMark]

One is offset. The other is drawn from the upper right hand corner of your base.

[JD Mather]

Hint #2

1. What is the length of the yellow lines?

2. What is the length of the green line?

3. What are these lines (in other terms)?

 

(BTW - I do not understand the TTR hint.)

 

[JD Mather]

Answers

1. 65

2. 31

3. radii

 

Q4. What is 65+31=?

[prime333]

I can see that, but WHY is it offset and WHY is the other one on the right hand corner? Sorry if I sound dump, but can you please explain? Thank you.

[ReMark]

It all has to do with the radius of the circle you have to draw. Which is.........?

 

You are constructing the centerpoint of that circle.

[JD Mather]

I can see that, but WHY is it offset?

 

I didn't offset anything but I guess I could have offset rather than adding 65+31.

[JD Mather]

Here is what you know.

 

If you take a piece of string 65mm long and anchor one end at the upper right corner of your rectangle and with the other end draw an arc - how far from the corner of the rectangle would any point on that arc be from the corner?

[JD Mather]

So somewhere on that arc traced by the end of the string - must be the center point that you are looking for.

 

Now if you do the same thing with a piece of string length 31+65 from the center of the R31 arc, somewhere on this new circle must be the center of your R65 arc.

 

Well if the unknown center location is on the first traced arc AND the unknown center location is on the second traced arc - there are only two intersections where that is possible. One is now obvious and the other possible intersection is obviously not the solution.