A new learner wants to form the dual of a noun ending in اء. What must be checked before changing the hamzah?

Dual and Plural of Mamdud and Maqsur Nouns

• Whether the noun has three letters or more than three.
• Whether the hamzah is original, feminine, or neither.
• Whether the final alif represents an original waw or ya.
• Whether a sound masculine or sound feminine plural is being formed.