Let sum of 3 numbers be x.
Average of 3 numbers and 8 =

25 =

100 = x +8
x= 92.
The sum of 3 numbers is 92.
Answer:
By the Empirical Rule, 
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
The symbol of a standard deviation is
. So
When plotting sample statistics on a control chart, 99.7% of the sample statistic values are expected to fall within plus/minus how many sigma?
By the Empirical Rule, 
180/360
divide 180 top and bottom
180/180 = 1
360/180 = 2
1/2 sold is your answer
hope this helps
The value of x in the triangle is 61.9°.