According to Newton's Second Law of Motion, the net force acting over an object is responsible for the acceleration of the object:
[tex]\Sigma F=ma[/tex]Since the friction and the horizontal force act in opposite directions, then:
[tex]\Sigma F=F_H-f[/tex]Where F_H represents the horizontal force and f represents the friction.
Replace the expression for the net force and isolate f:
[tex]\begin{gathered} F_H-f=ma \\ \Rightarrow f=F_H-ma \end{gathered}[/tex]To find the magnitude of the friction, replace F_H=89.7N, m=22.5kg and a=1.23m/s^2:
[tex]\begin{gathered} \Rightarrow f=(89.7N)-(22.5\operatorname{kg})(1.23\frac{m}{s^2}) \\ =89.7N-27.675N \\ =62.025N \\ \approx62.0N \end{gathered}[/tex]Therefore, the magnitude of the force of kinetic friction acting on the crate is 62.0 N.