a) (x-8)^2+(y-4)^2=25
b)i)m(FB)=4/3 and equation of tangent BC is 3x+4y=65
ii)37.74cm
You don't need pythagoras. Unless by pythagoras you mean equation to calculate a line so pythagoras twice, but I doubt OP knows that that is pythagoras (no offense OP)