In right #\triangle ABC#, we have #\angle A=26^\circ# & #a=3# then other acute angle #\angle C# is given as
#\angle C=180^\circ-\angle B-\angle A#
#=180^\circ-90^\circ-26^\circ#
#=64^\circ#
Now, by applying Sine rule in right #\triangle ABC# as follows
#\frac{a}{\sin \angleA}=\frac{b}{\sin \angleB}=\frac{c}{\sin \angleC}#
#\frac{3}{\sin 26^\circ}=\frac{b}{\sin 64^\circ}=\frac{c}{\sin 90^\circ}#
Consider,
#\frac{3}{\sin 26^\circ}=\frac{b}{\sin 64^\circ}#
#b=\frac{3\sin64^\circ}{\sin26^\circ}#
#=6.151#
Consider,
#\frac{3}{\sin 26^\circ}=\frac{c}{\sin 90^\circ}#
#c=\frac{3\sin90^\circ}{\sin26^\circ}#
#=6.843#