34/5 is the answer, I think sorry if I’m not correct
Answer:
Her centripetal acceleration during the turn at each end of the track is 
Step-by-step explanation:
Total distance covered in one round , D= 400 m
Time taken to cover one round , T = 1 min 40 s = 100 sec
Speed of runner , 
Now centripetal acceleration is given by

where 


Thus her centripetal acceleration during the turn at each end of the track is 
A fraction that is greater then 1/2 but less then 3/4 is 5/8.
The answer to your question would be A.
I presume you mean 9 'square'
9^2= 9 X 9 = 81
Cheerio ✌️