You’re answer is B, you just have to multiply all of the sides together and then add your sums.
Hope this helps:)
Use the cosine law to find the length of side c:

![\begin{gathered} c^2=1^2+9^2-2(1)(9)\cos 60 \\ c^2=1+81-18\cos 60 \\ c^2=82-18\cos 60 \\ c^2=82-9 \\ c^2=73 \\ c=\sqrt[]{73} \\ c\approx8.54 \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20c%5E2%3D1%5E2%2B9%5E2-2%281%29%289%29%5Ccos%2060%20%5C%5C%20c%5E2%3D1%2B81-18%5Ccos%2060%20%5C%5C%20c%5E2%3D82-18%5Ccos%2060%20%5C%5C%20c%5E2%3D82-9%20%5C%5C%20c%5E2%3D73%20%5C%5C%20c%3D%5Csqrt%5B%5D%7B73%7D%20%5C%5C%20c%5Capprox8.54%20%5Cend%7Bgathered%7D)
Use the cosine law to find the measure of angles A or B:
Answer:
A Normal approximation to binomial cannot be applied to approximate the distribution of <em>X</em>, the number of computer crashes in a day.
Step-by-step explanation:
Let <em>X</em> = number of computers that will crash in a day.
The probability of a computer crashing in a day is, <em>p </em>= 0.99.
A random sample of <em>n</em> = 131 is selected.
A random computer crashing in a day is independent of the others.
The random variable <em>X</em> follows a Binomial distribution with parameters <em>n</em> = 131 and <em>p</em> = 0.99.
But the sample size is quite large, i.e. <em>n</em> > 30.
So the distribution of <em>X</em> can be approximated by the normal distribution if the following conditions are fulfilled:
Check whether the conditions satisfy or not:

The second condition is not fulfilled.
A Normal approximation to binomial cannot be applied to approximate the distribution of <em>X</em>, the number of computer crashes in a day.
Mass of New student who joined the group will be :


81 divided by 4 is ....20.25