1) 2) 3) 4) Convert your length L into meters. Convert your three times into seconds. (Remember, one minute is 60 seconds. So; 1 minute and 15.25 seconds is ?5.25 seconds and not 115.25 seconds.) Period, T = time! 100 (Period is the time for one complete swing.) (There are 3 periods to calculate; T1 , T2, and T3.) Average Period, Ta, = (Tl + T2 + T3 )f 3