Logical (adjective)

1. Based on or using reason or logic.
2. Reasonable and sensible.
3. Following as a natural consequence or a necessary result.
4. Consistent with or according to the principles of logic.

Origin:

Late 16th century: from french logique or late latin logica, from greek logikē (tekhnē) "(art) of reason", from logos "word, reason".

Examples:

1. It is only logical to assume that.
2. A logical conclusion.
3. A logical explanation.
4. It is logical that the company will expand.
5. His argument was logical and well-reasoned.