With percent error I understand the A is the average density but how do you get T in that equation?

Data: A. Steel Ball 1 2 3 4 5 average Diameter(mm) 15.855 15.755 15.745 15.745 15.730 15.766 Volume 2086.9 2047.6 2043.37 2043.7 2037.9 2051.89 d(volume) 34.9 5.3 8.3 8.3 15 14.4 Mass(g) 15.050 15.060 15.050 15.055 15.055 15.054 Density(g/mm^ .00721 00735 00736 00737 00739 00734 3 d(density) .00013 .00001 .00002 .00003 .00035 .00018 Percent error: (T-A)/T *100 ---> (7800-7340)/7800 *100 = 5.9% B. Aluminum Block 1 2 3 4 5 average L1(cm) 4.75 4.77 4.76 4.77 4.76 4.762 L2(cm) 1.60 1.61 1.60 1.60 1.60 1.602 L3(cm) 1.61 1.60 1.60 1.61 1.60 1.604 Volume 12.236 12.288 12.186 12.288 12.186 12.237 d(volume) .001 .051 .051 051 .051 .041 Mass(g) 30.970 30.960 30.960 30.950 30.960 30.690 Density(g/cm^ 2.531 2.520 2.541 2.519 2.541 2.5304 3) d(density) .001 .01 .011 .011 .011 .0088 Percent error: (T-A)/T *100 ---> (2700-2530)/2700 *100 = 6.3%