Given data:
The estimate weight of the puppy is E=20 pound.
The actual weight is A=25.4 pounds.
The expression for the percentage error is,
[tex]e=\frac{A-E}{A}\times100[/tex]Substitute the given values in the above expression.
[tex]\begin{gathered} e=\frac{25.4-20}{25.4}\times100 \\ =\frac{5.4}{25.4}\times100 \\ =21.26 \end{gathered}[/tex]Thus, the percentage error is 21.26%.