Given two circles:
x1, y1) with radius1x2, y2) with radius2
Here here i was making character generation tool, based on circle intersections... you may find it useful.
with dynamically provided circles:
C: {
C1: {id: 'C1',x:105,y:357,r:100,color:'red'},
C2: {id: 'C2',x:137,y:281,r:50, color:'lime'},
C3: {id: 'C3',x:212,y:270,r:75, color:'#00BCD4'}
},
Check FULL fiddle... FIDDLE