Percent Error =
[tex]( \frac{ |experimental \: value - accepted \: value| }{accepted \: value} ) \times (100)[/tex]
So, Ari's experimental value is ,
[tex] \frac{2.49g/ {cm}^{3} + 2.56g/ {cm}^{3} +2.72g/ {cm}^{3} }{3} =2.59g/ {cm}^{3} (average)[/tex]
The accepted value is,
[tex]2.65g/ {cm}^{3} [/tex]
Here's The Work
[tex]( \frac{ |2.59g/ {cm}^{3} -2.65g/ {cm}^{3} | }{2.65g/ {cm}^{3} } ) \times (100) = 2.26 \: percent \: of \: error[/tex]
Ari's Average Measurements Have An Percent Error Of 2.26%