Answer :
Step-by-step explanation:
[tex]length \: between \: ( - 2, - 1) \: and \: (6,4) \\ = \sqrt{(x _{1} - x _{2} )² + (y _{1} - y _{2})² } \\ = \sqrt{( - 2 - 6)²+ ( - 1 - 4)²} \\ = \sqrt{64 + 25} \\ = \sqrt{100} \\ = 10 \: units \\ radius = 10 \: units \\ diameter = 2 \times radius \\ d = 2 \times 10 \\ d = 20 \: units[/tex]