Measured reading is 1.65 kg
actual reading was 1.72 kg
error in the reading is 1.72 - 1.65 = 0.07 kg
Now percentage error is given as
[tex]error = \frac{error}{true reading}*100[/tex]
[tex]error = \frac{0.07}{1.72}*100[/tex]
[tex]error = 4.1[/tex]
so this is -4.1% error as the measured reading is less than the actual value