It's the same as cot (-150 or -5pi/6) and that's a reference angle of 30 so cot 30 or pi/6 is sqrt (3) and since it's in the 3rd quadrant, it's positive.
Answer:
So then the correct answer would be:
B) .9996
Step-by-step explanation:
The exact way to solve this problem is using the binomial distribution, assuming that our random variable of interest is "number of students living in apartments" represented by X and 
And we want this probability:
So we see that we satisfy the conditions and then we can apply the approximation.
If we appply the approximation the new mean and standard deviation are:
And then 
And we are interested on the following probability:
So then the correct answer would be:
B) .9996
Yes it's a right triangle. Using the Pythagoran
10^2 + 24^2 = 26^2
Thus it's a right triangle
Wiwona can make 305 bracelets because if we divide 2140 divided by 7 is 305