I am trying to use Excel 2000 to calculate the radius of the arc created by
taking a slice off the top of the circle.

I know the height of the slice (y1) and the length of the base of the slice.

If the point at which the base intersects the circle is designated 'A', the
Radius at point A is calculated as: R² = x² +y² where
x=0.5 x base length (8.0units) and
y=(Radius minus the height of the slice) = (R-2.4units)

R² therefore equals (8² + (R-2.4)² ) - Answer is 14.5333 by simultaneous
equations.

Trouble is, to calculate this in Excel results in a circular referece for
the value of 'R'.

Can anyone assist me to create a formula as I need to look at 100's of other
values?

Thanks in anticipation