Collocations for reasonable - adj.

appear, be, look, seem, sound
consider sth, judge sth, regard sth as, think sth

extremely, fairly, very, etc.
eminently
entirely, perfectly, totally (esp. AmE)
The police apparently thought this explanation perfectly reasonable.

enough
Her request sounded reasonable enough to me.

only
If companies expect work during personal time, it's only reasonable to allow personal time at work.

Reasonable is used with these nouns:
accuracy, alternative, amount, answer, approximation, argument, assumption, assurance, balance, belief, care, cause, certainty, chance, charge, comfort, compromise, conclusion, condition, confidence, deduction, demand, disagreement, distance, doubt, estimate, excuse, expectation, expense, explanation, fee, force, ground, guess, hope, inference, interpretation, length, level, limit, manner, notice, number, observer, offer, opportunity, percentage, person, possibility, precaution, price, profit, proportion, prospect, rate, recompense, request, requirement, restriction, return, safety, salary, settlement, size, standard, starting point, step, suggestion, sum, supposition, time, tone