Answer:
tan 25° = b / 8 m
Explanation:
You need to know what the ratios are.
sin X = opp/hyp
cos X = adj/opp
tan X = opp/adj
For angle B, the opposite leg is b, ad the adjacent leg is 8 m.
The hypotenuse is AB.
sin B = sin 25° = opp/hyp = b/AB
tan B = tan 25° = opp/adj = b / 8 m