Answer:
because the 1st corner and the 2nd corner is places in a straight line which the total angle is 180° so since the 1st corner has same angle as the 13th one the 14th is must be have same angle as the 2nd corner. so that the 1st corner + the 14th corner is equal as 180°
Step-by-step explanation:
IM thinking like the other guy and i agree with him
