B :81 EXPLANATION
The angle with the greatest measure corresponds to the longest:
Since we know the three side lengths, we use the cosine rule to obtain;
{a}^{2} = {b}^{2} + {c}^{2} - 2bc \cos(A)
where a=21, b=18 and c=14
{21}^{2} = {18}^{2} + {14}^{2} - 2 \times 18 \times 14\cos(A)
44 1= 324+ 196 - 504\cos(A)
44 1= 520 - 504\cos(A)
44 1 - 520 = - 504\cos(A)
- 79 = - 504\cos(A)
\cos(A) = 0.1567
A = \cos ^{ - 1} (0.1567) = 80.98 \degree
Answer:
<em>3</em>
Step-by-step explanation:
Use a calculator to do 7 divided by 12. You should get
0.58333333...
Only the 3 repeats forever, so the answer is 3.
First you plug in the known variables. So 192 for x and 3 for t. Lastly you get y = 192(3)
Using the normal distribution, it is found that there is a 0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean and standard deviation is given by:
- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The mean and the standard deviation are given, respectively, by:
The probability of a bulb lasting for at most 569 hours is the <u>p-value of Z when X = 569</u>, hence:
Z = 1.16
Z = 1.16 has a p-value of 0.877.
0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
More can be learned about the normal distribution at brainly.com/question/24663213
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