When teaching a new vocabulary, how many times should a teacher encourage the student to repeat the word

It depends on student brain capability to understand the teacher, atleast 2 times is enough for a Brilliant student and an average student would take atmost 5 while the dull ones it would have to repeated until he or she gets it

The probability of hitting the black circle is closer to 0 than it is to 1. because: find area of circle ~ 3.14*r^2
which is 3.14 because the radius squared is 1. so 1*3.14= 3.14
 and the area of the whiteness is 121.
subtract 3.14 from 121 and you get 117.86 
this answer is closer to a 0 probability than the white space. the white space is closer to a probability of 1.