The circle ${\mathrm{x}}^2+{\mathrm{y}}^2+2\mathrm{x}+4\mathrm{y}-20=0\text{ and }{\mathrm{x}}^2+{\mathrm{y}}^2+6\mathrm{x}-8\mathrm{y}+10=0 :$

are such that the length of their common tangent is $5{\left(\frac{12}{5}\right)}^{1/4}$

are such that the length of their common chord is $5\sqrt{\frac{3}{2}}$

are such that the number of common tangents on them is 2

are orthogonal