I did the oscillation for the time sec for 10 cycles. I want to know how do I calculated the Period, T and calculate the gravity, g

Data Table C : Length of Pendulum = 8OCM Disp. of Time (sec) for 10 Cycles Period, T Calculated pendulum Trial #1 Average of 3 (cm) Trial #2 Trial #3 (sec) Trials gravity, g 9-27 80 cm | 9.10 60 cm 8.90 8 602 8 70 |8 40cm 6. 98 | 6- 56 6.20 6-59 35 cm 5. 25 5 79 5.81 5.62Data Table A : Object 1 Length of Time (sec) for 10 Cycles Taxp pendulum Average of 3 Taco Calculated Trial #1 Trial #2 Trial #3 (cm) Trials (sec) (sec) gravity, g 10.20 10.40 10-10 8ocm Tom 6ocm 18.10 140 cm 10 0! 35 Data Table B : Object 2 Length of Time (sec) for 10 Cycles pendulum Average of 3 Texp T acc Trial #1 Calculated (cm) Trial #2 Trial #3 Trials (sec) (sec) gravity , g 80 cm 7.08 7..08 7-00 7: 05 BOCM $5 57 5 - 50 5.57 4ocm / 16:08 4 - 08 35 (M B. 05 3.08 3 -08