Answer :

[tex]2*5=10 \\ \\ 10*5=50 \\ \\ 50*5=250 \\ \\ The \ rule \ is \ \boxed{*5} \\ [/tex]
the rule for the pattern is times 5 
thats because 2times 5 equal 10 times 5 equals 50 times 5 equals 250

hope it helps