Answer:
72
Step-by-step explanation:
5-4=1
9x1=9
9x2=18
18x4=72
240 bc you need to mulitpy it and ye
The rule of geometric sequence is ⇒⇒⇒ a * r^(n-1)
Where a is the first term and r is the common ratio
for the given sequence √5 , √10 , 2√5 , .......
a = √5
r = √10 / √5 = √2
The ninth term = √5 * (√2)^(9-1) = √5 * (√2)⁸ = 16 √5
the correct answer is the third option 16√5
-3 1/2 because if you do 2.8 times 1 and 1/4 you get 3.5 and 3.5 as a fraction is 3 1/2