Answer:
[tex]E = 55.9583\ Volts/meter[/tex]
Explanation:
First let's find the electric potential using y = 22.5:
[tex]V(y) = 1.69y^2 +15.6y+52.5[/tex]
[tex]V(22.5) = 1.69(22.5)^2 + 15.6*22.5 + 52.5[/tex]
[tex]V(22.5) = 1259.0625\ Volts[/tex]
Then, to find the magnitude of the electric field, we just need to divide the electric potential by the distance y:
[tex]E = V/d[/tex]
[tex]E = 1259.0625/22.5[/tex]
[tex]E = 55.9583\ Volts/meter[/tex]