Answer:
+) m∠1 = m∠2 (vertical angles theorem)
+) m∠2 and ∠3 are supplementary (because a//b)
+)m∠3 = m∠4 (alternate interior angles theorem, c//d)
=> ∠1 and ∠4 are supplementary (substitution property of equality)
Step-by-step explanation:
from what I know
A=4
B=3
C=2
and a plus adds 0.33 and a minus minuses 0.33
question wants us to find yearly average or average per 1 year
since these grades span over 2 years, we must divide the total average by 2
averagefresh=sum of fresh grades/4 grades per year
averagesoph=sum of soph grades/4 grades per year
yearlyaverage=(averagefresh+averagesoph)/2
freshman:
(C)+(B)+(A)+(C-)=2+3+4+(2-0.33)=10.67
sophomore:
(B+)+(A-)+(C+)+(B-)=(3+0.33)+(4-0.33)+(2+0.33)+(3-0.33)=12
averagefresh=10.67/4=2.6675
averagesoph=12/4=3
yearlyaverage=(2.6675+3)/2=2.83375
so it's about a 
average
Answer is option C 19.64 sq units
What????????????
Don't post unless you really need help<span />
The predicted value of hardness at 37 hours is 243.87 and an 85% confidence interval for the mean hardness is (242.12, 245.61). At 41 hours, the predicted hardness is 252 and an 85% confidence interval for mean hardness is (249.83, 254.18). The confidence interval for X is equals to 41 which is wider because the value 41 is farther away from the sample mean X than is 37. As an outcome, the standard error for the prediction is larger.
