وَبِالْجَمْعِ الْمُكَسَّرِ الْمُنْصَرِفِ، كَـ«رِجَالٍ».
Translation: The same rule applies to the fully declinable broken plural, such as “رِجَالٍ.”
رَجُلٌ means “a man,” while رِجَالٌ means “men.” The internal pattern changes in forming the plural; it is thus a broken plural.
رِجَالٌ is nominative, رِجَالًا accusative, and رِجَالٍ genitive. Do not overlook the condition that this broken plural is fully declinable.