Yes it does have to be parallel or else it would not be a rectangle.So it is true.
Hope this helped! :)
Your answer should be C. 3x^3√2
A(n)=a(1)+d(n-1), d=a(16)-a(15)=-5-(-53)=48
a(15)=a(1)+d*(15-1),
-53=a(1)+48*(15-1),
a(1)=-53-48*14= -725
a(n)=-725+48(n-1)
Answer: 271
Step-by-step explanation:
The formula we use to find the sample size is given by :-

, where
is the two-tailed z-value for significance level of 
p = prior estimation of the proportion
E = Margin of error.
If prior estimation of the proportion is unknown, then we take p= 0.5 , the formula becomes


Given : Margin of error : E= 0.05
Confidence level = 90%
Significance level 
Using z-value table , Two-tailed z-value for significance level of 

Then, the required sample size would be :

Simplify,

Hence, the required minimum sample size =271