Puzzle:
2. find the sum of the digits of each multiple of 9 below.
sum of digits
1 + 8 = 9
9.1 = 9
9.2 = 18
9.3 = 27
9.4 = 36
9.5 = 45
9.6 = 54
9.7 = 63
9.8 = 72
9.9 = 81
describe a pattern. (do you think it will continue? )

In the diagram of circle o, what is the measure of zabc?

If value of cos330° is √3/2 then find tan165°.

Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables