Heya!
Here is your answer:
The measure of all angles are 60°.
Here,
triangle ABC is an equilateral triangle (all sides are equal)
so, Its all angle measure same.
<A + <B + <C = 1800°
let <B = x
x+x+x =180°
3x = 180
x= 60°
Hence
<B = 60°
110 is the price that is charged for every time the commercial is aired. 900 is a base price that they charge to air the commercial.
As the mean is E[X] =150 and

= 30, using the normal distribution to get the answer is just using Z. So, what we need is P(X<180).
![Z= \frac{x-E[X]}{\sigma } = \frac{180-150}{30} = \frac{30}{30} = 1](https://tex.z-dn.net/?f=Z%3D%20%20%5Cfrac%7Bx-E%5BX%5D%7D%7B%5Csigma%20%7D%20%3D%20%5Cfrac%7B180-150%7D%7B30%7D%20%3D%20%20%5Cfrac%7B30%7D%7B30%7D%20%3D%201)
P(x<180) = P(z< 1) =

(1) = 0.8413.
Then, just multiplying the amount of books you have, which is 500, with the probability would give how many books are less than 180 pages, being:
Step-by-step explanation:
<u>Step 1: Find the correct option</u>
If you look at the attached photo, the option that fits those points is option B, therefore, the correct answer is B
Answer: Option B
<em>Look at the attachment:</em>