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Re: Math: Polygons [#permalink]
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Woooo,, wooo ,,, woooo!!!

U rock again,, well if u continue to do this, there will be no need for MGMAT guides, I think ;).

I wish u can write about number properties too.

Kudossss!!!!!

Posted from my mobile device
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Re: Math: Polygons [#permalink]
Wow this is really helpful. I've been studying for the GMAT for a couple of months now and I had no idea what the formula for a trapezoid was.

kudos +1
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Re: Math: Polygons [#permalink]
Excellent post. Kudos +1
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Re: Math: Polygons [#permalink]
Thank You. one less hole in my GMAT armor. I feel as though I am getting ready for battle! :twisted:
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Re: Math: Polygons [#permalink]
thanks. You are amazing.
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Re: Math: Polygons [#permalink]
Wonderful. Thank you again!
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Re: Math: Polygons [#permalink]
Ahan...Good one !
Thanks :)
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Re: Math: Polygons [#permalink]
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Nice post ! Keep up the good work.
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Re: Math: Polygons [#permalink]
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nice post, as usual, Bunuel...

i m becoming a great fan of ur posts...

a small suggestion from my side... in the explanation of trapezoid, the diagram shows bases as a and b and height as h, but in the formula for area you considered different variables, though this doesn't point out any mistake in the formula, it would be clear if u considered the same variables...

with such wonderful posts gmatclub can start its own quant book i suppose.... wow...

i almost forgot.... kudossssssssss..... +1
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Re: Math: Polygons [#permalink]
Going through Polygons tutorial .

Question:
Quote:
The apothem of a polygon is a line from the center to the midpoint of a side. This is also the inradius - the radius of the incircle.

Generally speaking, inradius is result of dividing the angle whereas circumcenter is the result of divding the side. That said, the above definition (under quotes) is for circumradius not inradius. Isn't it ?
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Re: Math: Polygons [#permalink]
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GMATMadeeasy
Going through Polygons tutorial .

Question:
Quote:
The apothem of a polygon is a line from the center to the midpoint of a side. This is also the inradius - the radius of the incircle.

Generally speaking, inradius is result of dividing the angle whereas circumcenter is the result of divding the side. That said, the above definition (under quotes) is for circumradius not inradius. Isn't it ?

Inradius - radius of an incircle, a circle inscribed in polygon (triangle, square, ...);

Circumradius - radius of a circumcircle, a circle circumscribing a polygon.

So I think everything is right.
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Re: Math: Polygons [#permalink]
again, many thanks for this!
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Re: Math: Polygons [#permalink]
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Great post , as always!, by Bunuel. Thanks :)
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Re: Math: Polygons [#permalink]
Thanks for the post Bunuel. I have a doubt. Do the diagonals bisect each other in a trapezoid?

Bunuel
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nice post, as usual, Bunuel...

i m becoming a great fan of ur posts...

a small suggestion from my side... in the explanation of trapezoid, the diagram shows bases as a and b and height as h, but in the formula for area you considered different variables, though this doesn't point out any mistake in the formula, it would be clear if u considered the same variables...

with such wonderful posts gmatclub can start its own quant book i suppose.... wow...

i almost forgot.... kudossssssssss..... +1

Thanks. You are right, changed the variables as you suggested. +1 for good suggestion.

As for the quant book: actually we are working on our very own GMAT MATH BOOK. Of course much work has to be done till completing it: this topic isn't finished yet, we are working on Number Theory, other topics are waiting... But at the end we'll hope to get comprehensive guide to the quant topics of GMAT.
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Re: Math: Polygons [#permalink]
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Thanks for the post Bunuel. I have a doubt. Do the diagonals bisect each other in a trapezoid?

Bunuel
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nice post, as usual, Bunuel...

i m becoming a great fan of ur posts...

a small suggestion from my side... in the explanation of trapezoid, the diagram shows bases as a and b and height as h, but in the formula for area you considered different variables, though this doesn't point out any mistake in the formula, it would be clear if u considered the same variables...

with such wonderful posts gmatclub can start its own quant book i suppose.... wow...

i almost forgot.... kudossssssssss..... +1

Thanks. You are right, changed the variables as you suggested. +1 for good suggestion.

As for the quant book: actually we are working on our very own GMAT MATH BOOK. Of course much work has to be done till completing it: this topic isn't finished yet, we are working on Number Theory, other topics are waiting... But at the end we'll hope to get comprehensive guide to the quant topics of GMAT.

No, diagonals of trapezoid do not bisect each other.
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Re: Math: Polygons [#permalink]
So Bunuel, if it is given that diagonals bisect then is it definitely a parallelogram? in other words it is a necessary and sufficient condition for parallelogram?

what is the difference between a trapezoid and trapezium? do the diagonals bisect in a trapezium?
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Re: Math: Polygons [#permalink]
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So Bunuel, if it is given that diagonals bisect then is it definitely a parallelogram? in other words it is a necessary and sufficient condition for parallelogram?

what is the difference between a trapezoid and trapezium? do the diagonals bisect in a trapezium?

If diagonals of a quadrilateral bisect each other then this quadrilateral is a parallelogram.

It can also be a special typo of parallelogram: rectangle, square, or rhombus.

Trapezoid and trapezium are the same figure: diagonals of trapezoid do not bisect each other.
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