The ones in the question are correct. Well done!
irregular means not regular. regular means (look up in dictionary.com). BTW, check your spelling!
It is irregular.
Irregular verbs are verbs that change their spelling when written in past tense. These verbs do not follow the regular pattern of adding "-ed" to form the past tense.
Pentagons can be regular or irregular.
regular or irregular
It is irregular.
A pentagon can be regular or irregular.
That is the correct spelling of "irregular" (not standard, not typical).
It is an irregular polygon.
Irregular.
Irregular
"Have" is an irregular verb in English.