Answer:
A
Step-by-step explanation:
When finding out which number is the greatest, I would convert these numbers to numerals with decimals for easier comparison.
3[tex]\sqrt{5}[/tex] is approximately 6.71.
6[tex]\frac{1}{4}[/tex] is 6.25
6.55 is, well 6.55.
From here, we can tell that 6.71 is the greatest, followed by 6.55 and 6.25 is the smallest. Thus, the order in descending order should be 3[tex]\sqrt{5}[/tex], 6.55 then 6[tex]\frac{1}{4}[/tex], which is Option A.