Thread: Can't make sense of some of these pre-test questions (long)

1. Can't make sense of some of these pre-test questions (long)

Hi,

I'm going through a pre-test located here: http://paccadult.lbpsb.qc.ca/eng/ext...109Pretest.ppt with answer key located here: http://paccadult.lbpsb.qc.ca/eng/ext...0solutions.ppt. I've included screen shots in case you're not comfortable downloading the files. My problem is I can't make sense of questions...

Question 6 & 7:
Question Sheet: http://i.imgur.com/yb0JpSM.png

For six my question is easy, do you go clockwise or counter-clockwise when deciding what mBC consists of as far as circumference? In other words, how do I know if it's major arc BC or minor arc BC?

For 7b, it seems like the radii of the larger circle to the smaller circle have a ratio of 3/1, or k=3. So area should be k^2, or 9 time greater than the small, but this is false? I don't understand that. Is it because it has a hole in the middle so you have to factor that in? I don't understand the explanation for 7d either, could someone help clear that up?

Question 8:
http://i.imgur.com/iPp8STv.png

For this question, I got it to a point where the terms were correct but the signs were not right. I understand up to the substitution part, but by mjolnir I have no idea what they subsistuted in and where they got it.

I've only gotten to question 10 of 14, so I'm sure there will be more but I have to go to bed. The exam is in less than 48 hours so I would really appreciate the help with this one. I haven't done any geometry other than since this was introduced to me on Friday in years, and the exam is after 5 days so this is a bit rough and I appreciate your help.

Thanks!

2. Re: Can't make sense of some of these pre-test questions (long)

"The" angle on a circle is always the "minor arc".

Yes, the radius of the larger circle is 3 times the radius of the smaller circle. It follows that the area of the larger circle is 9 times the area of the smaller circle. But that is NOT the area of the shaded region. The shaded region is the larger circle minus the smaller circle. So if we call the area of the smaller circle "A", the area of the larger circle is 9A. That means that the area of the shaded region is 9A- A= 8A.