To answer this question, we need to find the difference of both values respecting the one for Pluto as follows:
1. We have that the diameter of Eris is 2,338km.
2. We have that the diameter of Pluto is 2,379.8km.
Then, as a percent difference:
[tex]\%P_{\text{diff}}=\frac{D_{Pluto}-D_{\text{Eris}}}{\text{D}_{\text{Pluto}}}\cdot100[/tex][tex]\%P_{\text{diff}}=\frac{2379.8-2338}{2379.8}\cdot100[/tex]Therefore:
[tex]\%P_{\text{diff}}=1.75645012186[/tex]If we round the final result to two decimal places, we finally have:
[tex]\%P_{\text{diff}}=1.76[/tex]