How many Senators must vote for a choice to have a declared winner for vice president?

To find 55% of 679, multiply

679 x 0.55 = 373.45

Sarah needs at least 374 votes to win.

Hope this helps!

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.