Answer:
D, <VMY cannot be a right angle, its an obtuse angle (more specifically, ab a 120 degree angle)
C. just shorten fraction and you'll only get 1/(y²z²)
you'll get (6xy²z²)/(6xy⁴z⁴)=1/(y²z²)
Why not look up "standard deviation" yourself, to be sure? But yes, the std. dev. is the sqrt of the variance.
B) 1197 Cubic Ft.
Explanation: You have to make 13 and 10 to the power of 3. 13^3 = 2197 and 10^3= 1000. Then you subtract and get 1197
