The past participle is one word, except for phrasal verbs. The past particples in the above sentences are: 1. struck, 2. told, 3. set up, 4. built, 5. built.
If you write a sentence in any of the perfect tenses, both the active and the passive voice will use the past participle.
Here are some sentences in the simple tenses: Active / Passive
1. The teacher gives me a book. / I am given a book by the teacher.
2. The teacher gave me a book. / I was given a book by the teacher him.
3. The teacher will give me a book. / I will be given a book by the teacher.
('Given' is the past participle of 'give')
give/gave/given - present tense, past tense, past patrticiple
The reason you ended up with same form in your simple tense sentences 1. and 3. is that you chose verbs that have the same form:
Student or Learner