Intersection of the circle C1 and radius R1 and the circle with center C2 and radius R2
Write the values in the boxes.  Then press    -  Clear all:   Clear C1/C2:
C1x = C1y =     R1 =

C2x = C2y =     R2 =

P =  , 

Q =  , 

dist. C1-C2 =    

=   A
(you can use "A" as one or both inputs)
If you have to put a coefficient using some other function symbol (for example √2; π/2), put it in a numerical form (1.414213562373095, 1.5707963267949), for example using this (or this).  [NaN = "not a number"]