Answer:
Choice B. sin(B)=cos(90-B)
Step-by-step explanation:
That cofunction identity is the one you looking for...choice B.
If you aren't convinced or don't know that identity, then maybe this will help:
90-B is actually the same thing as saying A for this right triangle since A+B=90.
So choice B basically says sin(B)=cos(A)
Well let's find both sin(B) and cos(A)
sin(B)=b/c
cos(A)=b/c
Those are the same ratios!
So they are equal!
Answer:
m∠BFE = 171º
BE = 219º
Step-by-step explanation:
∠BFE is supplementary to ∠EFC
m∠BFE = 180 - 9
m∠BFE = 171º
--------------------------
The angle between two chords is equal to half the sum of the intercepted arcs:
∠BFE = (DC + BE)2
171 = (123 + BE)/2
342 = 123 + BE
219º = BE
<em>Your answer will be, </em><em>"6p - 8"</em>
Thanks,
<em>Deku ❤</em>
Answer:
A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error of the interval is given by:
In this problem, we have that:
99.5% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.07?
This is n when M = 0.07. So
A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07
