I forgot to offer one Rak`ah (unit

Q 3: I went to offer Salah (Prayer) in congregation, but I missed the first Rak`ah (unit of Prayer). After the Salah was concluded, the Imam (the one who leads congregational Prayer) mistakenly performed an additional Rak`ah and so the congregation had offered five Rak`ahs, but I had only offered four. Was my Salah complete even though the congregation had offered five Rak`ahs?

(Part No. 7; Page No. 136)  A: It is obligatory on you to repeat the Salah, because the fourth Rak`ah you performed is Batil (null and void) as it was an extra Rak`ah on the part of the Imam and it will not be considered. The Ma'mum (a person being led by an Imam in Prayer) should make up for what they miss after the Imam says the Taslim (salutation of peace ending the Prayer). However, if someone knows this rule and offers the Rak`ah they miss without a long gap of time after the Imam says the Taslim, then their Salah will be sufficient and they will not have to repeat it.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.