Lesson: Quadrilaterals

Comment on Quadrilaterals

https://gre.myprepclub.com/forum/the-perimeter-of-a-rect-angle-that-has-an-area-of-48-and-a-14126.html

Hej Brent,

could you perhaps help me solve this exercise?

thanks!

So for the formula (diagonal1 x diagonal2) ÷ 2

I'm assuming this work with squares as well?
greenlight-admin's picture

That's correct. Since a square is a type of rhombus, the formula works for squares as well.

FYI: the rhombus is very rarely tested on the GRE
greenlight-admin's picture

True

Hi Brent, Could you post a solution to this? https://gre.myprepclub.com/forum/in-the-xy-plane-one-of-the-vertices-of-square-s-is-the-2192.html

I'm not sure how the point 10,10 is found as explained in the solution
greenlight-admin's picture

thanks!

Hey Brent! had a question on your solution this: https://gre.myprepclub.com/forum/l1-is-parallel-to-l2-18507.html

Couldnt you move point Z further to get the smaller angle as well? In this case, wouldn't the shaded region change?
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/l1-is-parallel-to-l2-18507.html
If we did that, we'd no longer have the required 89-degree angle.

https://gre.myprepclub.com/forum/l1-is-parallel-to-l2-18507.html

In this problem, isn't the 89 angle outside of the triangle indicate that inside the triangle, the angle is 91 since it should add up to 180? on a line? That's what confused me because it seems to be indicating the 89 degree angle is outside the angle outside.
greenlight-admin's picture

You're correct to say that the 89 angle is outside of the triangle, and this means angle inside the triangle is 91 degrees.

In that case, wouldn't that make the answer B?
greenlight-admin's picture

No, the answer is still A.

If you take a look at my solution (https://gre.myprepclub.com/forum/l1-is-parallel-to-l2-18507.html#p52616), you'll see that, when the given angle is 90°, the shaded area = the unshaded area.

When we make the angle 89°, the bottom of that line must swing a little to the left, which makes the unshaded area a little smaller,

Does that help?

In other words, we want x/y = y/(x/2)

In this problem, how did you come up with y/x/2? Shouldn't it be x/2/y?
greenlight-admin's picture

I'm not sure what question/solution you're referring to. Can you provide a link?

https://gre.myprepclub.com/forum/a-project-requires-a-rectangular-sheet-of-cardboard-satisfyi-12275.html
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/a-project-requires-a-rectangular-sheet-...

If you look at the graphic I created ([img]https://i.imgur.com/evnoVV0.png[/img]), you'll see that the longest side of the ORIGINAL rectangle has length x (and the shorter side has length y).

When we divide the original rectangle into 2 equal rectangles, the longer side of the RESULTING rectangle has length y (and the shorter side has length x/2)

So, in the ORIGINAL rectangle (longer side)/(shorter side) = x/y
And, in the RESULTING rectangle (longer side)/(shorter side) = y/(x/2)

Since we're told the two ratios are equal we get: x/y = y/(x/2)

Does that help?

Hi Brent,
my question is not related to the topic by I am frustrated and have a general estimating question based on your experience to make! my test day is in about 2 weeks. I have completed most of the courses - besides algebra/equation, world problems, statistics and probability-! so far I am pretty confident with the 130-149 dif.level exercises, doing most of the 150-159 dif. level questions and finding 160-170 pretty challenging and difficult to solve ( even though I kind of have and idea how to solve but cannot proceed). Based on the fact that I will try to finish the whole course and practice the exercises; What are the chances that I score 650 in quant?

I would highly appreciate your opinion. Thank you very much.
greenlight-admin's picture

Hi Kristina,
I'll assume you meant to say "score 160 in quant" (please correct me if I'm wrong)
It's very hard to predict one's score based on their success rate with practice questions. Keep in mind that time management is a pretty big factor on the GRE. So, even if someone is successfully answering most questions at the 160-170 level, it's unlikely this person would score a Q160 if they typically spent 3 or 4 minutes answering each question.
The only way to get a good idea of your present GRE skills is to take an official practice test.

Oh, excuse me, I meant 165. You are right I obviously need to have a practice test I am just trying to finish the whole study guide 1.....

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