Answer:
There are many answers, so I'll put all of the ones I can think of here. (underline = change)
I ran to the table. Dinner was getting cold.
I ran to the table because dinner was getting cold.
I ran to the table; dinner was getting cold.
I ran to the table, for dinner was getting cold.
I ran to the table since dinner was getting cold.
note: do not use a comma to cut in between these two sentences. It is wrong and still a run-on; this incorrect tactic is called a comma splice.