Complex Math (NAV) Problem

[Syllogism]

Without using a calculator (trig functions):

Does anyone know the quick mental-formula for determining the heading required to proceed from one point in space to another point in space when navigating off a single VOR?

Example:

What heading is required to go directly from the 090 radial 20 DME fix - to the 180 radial 70 DME fix?

I am at a total loss...?

 

[kingairyahoo]

No clue (and hate to ask) but why would one need to know anymore...

...i havent had to fly a radial (not counting sim) in dam near 15 years

 

[rice]

No math formula but back in the day we used to call that a TACAN point to point. On the HSI put the point you want to go to on the outer edge of the compass rose (180R/70) then visualize your present position (090R/20), proportionally, on the rose. Draw a line btwn the two points. then slide it up to bisect the center point of the rose. The number the line points to is your initial heading.