Area of Circle-Circle Intersection?



>I'm trying to use Maxima with the following equation for the area of 
>the circle-circle intersection, to solve for the radius R of two 
>circles with equal radius, when the following is known:
>
>the distance d between the centers of the circles is 45.9 feet
>the area of the circle-circle intersection is 15% of the area of 
>either circle (i.e. Area Intersection = 0.15(pi)R^2
>
>Using Maple 11, I get the output shown at 
>http://upload.imgspot.com/u/07/321/15/maple.jpg
This appears to be the correct answer for R.

>However, when I try to use Maxima to solve this, I cannot get beyond 
>the point shown in (%o40) at
http://upload.imgspot.com/u/07/321/15/maxima.jpg

>Can anyone give me an idea of what I might not be doing correctly 
>with Maxima?  I have tried simplifying and everything else I can 
>think of, but cannot get Maxima to solve beyond this point.
>
>Thank you,
>Tony