Complete Question
The complete question is shown on the first uploaded image
Answer:
The calcium level that is the borderline between low calcium levels and those not considered low is 
Step-by-step explanation:
From the question we are told that
The mean is 
The standard deviation 
The proportion of the population with low calcium level is
5% = 0.05
Let X be a X random calcium level
Now the P(X < c) = 0.05
Here P denotes probability
c is population with calcium level at the borderline
Since the calcium level is normally distributed the z-value is evaluated as

The critical value for 0.05 from the standard normal distribution table is

=> 
substituting values

=> 
=> 
=(140+4) / 8
=(144/8) + (4/8)
=18 + 2
=<span>20</span>
Because they’re both the opposites of eachothers quantities
Answer:
The answer is B. 9
Use cosine rule. In this case, I am using SOH and the right triangle:
sin 60°= a ÷ 6 root 3
(6 root 3)(sin 60°)= a
a=9
Step-by-step explanation: