The similarities are VWX ~ YVX ~ YWV. Matching corresponding letters, you have
WX/WV = VX/VY = WV/WY
The appropriate choice is ...
B. VX/VY = WV/WY
This is the answer i believe!! (p.s. cymath is a great website to use for this kind of stuff:)
Answer: b) 84
Step-by-step explanation:
Let p be the prior estimate of the required proportion.
As per given , we have
p =0.5 (The probability of getting heads on a fair coin is 0.5)
Significance level : 
Critical z-value (using z-value table ) : 
Confidence interval width : w= 0.18
Thus , the margin of error : 
Formula to find the sample size ( if prior estimate of proportion is known.):-

Substitute the values , we get

Simplify ,
[Round of to the next whole number.]
Hence, the number of times we would have to flip the coin =<u>84</u>
hence, the correct answer is b) 84