Answer:
< CFE = 40°
Step-by-step explanation:
To better understand the solution, see attachment for the diagram.
Given:
BC parallel to DE
Measure of Arc BD = 58°
Measure of Arc DE = 142°
First step: Draw a diameter that passes through the centre of the circle and name it. In this case, the diameter is line ST.
The line ST divides the arc BD and arc DE into half.
That is:
Arc SC = 1/2(arc BC) =1/2(58)
Arc SC = 29°
Arc TE = 1/2(arc DE) =1/2(142)
Arc TE = 71°
Arc SC + Arc CE + Arc TE = 180° (Sum of angles in a semicircle
29° + Arc CE + 71° = 180°
Arc CE + 100° = 180°
Arc CE = 180-100
Arc CE = 80°
Inscribed angle = 1/2(intercepted angle)
<CFE = 1/2(Arc CE )
<CFE = 1/2(80)
< CFE = 40°
You ended without giving the values, so we can't get the exact answer. However, I can tell you steps.
First, you need to find the z-score. Then, look up the z-score on a normal distribution table and you will get the percent.
Let's call your value X. Just plug X into the equation below and you will have your z-score.
(x - 20.5) / 3.5 = z
Now, look up the z-score and you will have your probability.<span />
I know you got this from Khan Academy, and so the answer is $9.81. You probably don't care about how it is done, and you probably just want to put the answer and be done, but I will show you. You have to take the original price of $9 and multiply it with 9%, or 0.09, to get the amount of your tip. add the 9%, or $81. You can also just do 9*109%, or 9*1.09, to put these two steps together and add the original price and the tip.