Email email@example.com for your file Ref 1Q5
Open the fie ACA1-04.dwg. Draw an arc using start/centre/end option. Start your arc at the centre of the circle marked 1. It must then past through the centre point of the blue dashed line arc. Then end at the centre of the circle marked 2.
What is the radius of the arc you have just created?
It's more difficult to find the centre of the blue arc as it has a comparatively large radius. Note that centre of arc or circle osnap points will not show until you move the cursor over the arc or circle. A cross will then appear at the centre osnap point.
Such exercises can be used in job interviews to test whether the a candidate has diligence to find the centre point of a circle or arc and not as in this case the end of the dashed blue arc.
You will probably have to zoom out to find the blue arc centre osnap point as the arc radius is relatively large. You may have to do a manual regen by typing the shortcut RE, if the mouse movement freezes.
It will help to draw a small circle at the centre of the blue arc before you start the arc command.
Use Arc - start/centre/end option to draw the arc as above.
Click & grip the new arc created. - It will be continuous as per the status line- read off the radius from the properties box.