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What is the area of parallelogram ABCD ? [#permalink]
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What is the area of parallelogram ABCD ? (1) AB = BC = CD = DA = 1 (2) AC = BD = (2^1/2)
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Re: Gmat club Please explain [#permalink]
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Re: Gmat club Please explain [#permalink]
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05 Oct 2009, 00:56
"Area of rhombus d1*d2/2 (d1 and d2 are the lengths of a diagonals)"
Didn't know that! Thanks.



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Re: Gmat club Please explain [#permalink]
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22 Feb 2013, 00:37
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Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of a diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 C. Bunuel, A rhombus and a square with same lengths have different areas?
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Re: Gmat club Please explain [#permalink]
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22 Feb 2013, 01:02
Sachin9 wrote: Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of a diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 C. Bunuel, A rhombus and a square with same lengths have different areas? Good question. If you squeeze a square along its diagonal you'll get a rhombus. Different rhombuses you'll get while doing that, will have different area. So, the answer to your question is yes. Hope it's clear.
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Re: What is the area of parallelogram ABCD ? 1) AB = BC = CD = [#permalink]
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22 Feb 2013, 02:01
Pardon me. I didn't get you, Bunuel.. Are you saying that the square and different shapes of rhombuses with same length will have different areas?
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Re: What is the area of parallelogram ABCD ? 1) AB = BC = CD = [#permalink]
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Re: What is the area of parallelogram ABCD ? 1) AB = BC = CD = [#permalink]
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22 Feb 2013, 02:12
Bunuel wrote: Sachin9 wrote: Pardon me. I didn't get you, Bunuel..
Are you saying that the square and different shapes of rhombuses with same length will have different areas? Yes, that's what I'm saying. ok thanks.. Now 2 questions: 1)if the square and different shapes of rhombuses with same length will have different areas, the square will have the largest area . Guess this is correct. 2)this question seems dubious now to me.. A square is also a parallelogram and even a rhombus is.. so how can we be sure that ABCD is not a square and is a rhombus.
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Re: What is the area of parallelogram ABCD ? 1) AB = BC = CD = [#permalink]
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22 Feb 2013, 02:23
Sachin9 wrote: Bunuel wrote: Sachin9 wrote: Pardon me. I didn't get you, Bunuel..
Are you saying that the square and different shapes of rhombuses with same length will have different areas? Yes, that's what I'm saying. ok thanks.. Now 2 questions: 1)if the square and different shapes of rhombuses with same length will have different areas, the square will have the largest area . Guess this is correct. 2)this question seems dubious now to me.. A square is also a parallelogram and even a rhombus is.. so how can we be sure that ABCD is not a square and is a rhombus. Not sure I understand what you are trying to say. Anyway: From (1) we have that the parallelogram is also a rhombus (because the sides are equal). From (2) we have that the parallelogram is also a rectangle (because the diagonals are equal). So, our parallelogram is a rhombus AND a rectangle, so it's a square!
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Re: Gmat club Please explain [#permalink]
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18 Jun 2014, 07:02
Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of a diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 Answer: C. HI Bunuel, Square root of 2 is diagonal. \sqrt{2}, 1,1 form right angle triangle in rectangle. as we follow this rule in GMAT,cant we follow here ,considering length and breadth to be 1 each??



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Re: Gmat club Please explain [#permalink]
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18 Jun 2014, 08:37
nidhi12 wrote: Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of a diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 Answer: C. HI Bunuel, Square root of 2 is diagonal. \sqrt{2}, 1,1 form right angle triangle in rectangle. as we follow this rule in GMAT,cant we follow here ,considering length and breadth to be 1 each?? First of all please read this: rulesforpostingpleasereadthisbeforeposting133935.html#p1096628 (Writing Mathematical Formulas on the Forum) Next, are you talking about the second statement? What does "\(\sqrt{2}\), 1, 1 form right angle triangle in rectangle" even mean? Or the next sentence in your post? Sorry, don't understand at all what you mean...
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Re: What is the area of parallelogram ABCD ? [#permalink]
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16 Sep 2014, 12:50
Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of the diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 Answer: C. Bunuel, Since a square is also parallelogram, we have sides of a sq so easily we can find the area. Shouldn't A be sufficient? Regards, Ravi



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Re: What is the area of parallelogram ABCD ? [#permalink]
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16 Sep 2014, 13:24
email2vm wrote: Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of the diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 Answer: C. Bunuel, Since a square is also parallelogram, we have sides of a sq so easily we can find the area. Shouldn't A be sufficient? Regards, Ravi For (1) we have a parallelogram with equal sides, so rhombus, not necessarily a square.
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Re: What is the area of parallelogram ABCD ? [#permalink]
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23 Nov 2014, 05:55
Bunuel, how can we be sure in such questions that AB or BC is a side? I encountered several such questions in gmatclub tests and if I remember correctly, there was a question which consisted of such trick.
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Re: What is the area of parallelogram ABCD ? [#permalink]
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Re: What is the area of parallelogram ABCD ? [#permalink]
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23 Nov 2014, 07:21
Ok. Thanks Bunuel. I do not have the links now, but when I encounter such things again I will post it here.
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Re: What is the area of parallelogram ABCD ? [#permalink]
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02 Dec 2014, 02:42
Hi Bunuel,
If the second statement states that the diagonal length is different from square root of 2, the right choice will be E?



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What is the area of parallelogram ABCD ? [#permalink]
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27 Jan 2015, 06:35
Dear Bunuel, I want to ask you about the second statment AC=BD=2^1/2.You said that this could be rectangular how we can get diagonals of rectangular with lengths equal to 2^1/2? Where the sides of rectangular are not equal. So, I think that we can get diagonals equals to 2^1/2 just if we have both sides are equals to 1. Therefore, I see that the form can not be rectangular. Please correct me if what I wrote is not right. Also, I want to ask you about the diagonals of rhombus do they should be equals? and how we can calculate diagonals of rhombus I mean which form we can use? Thank you
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Re: What is the area of parallelogram ABCD ? [#permalink]
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19 Feb 2015, 01:52
What if the length of diagonal in statement B was not 2^1/2? Would the answer still be C?



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Re: What is the area of parallelogram ABCD ? [#permalink]
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09 Sep 2015, 01:08
Bunuel wrote: tkarthi4u wrote: What is the area of parallelogram ABCD ? 1) AB = BC = CD = DA = 1 2) AC = BD = (2^1/2) (1) Says that ABCD is a rhombus. Area of rhombus d1*d2/2 (d1 and d2 are the lengths of the diagonals) or b*h (b is the length of the base, h is the altitude (height).) Insufficient (2) Says that ABCD is a rectangle. Area of a rectangle L*W (length*width) Insufficient. (1)+(2) ABCD is rectangle and rhombus > ABCD is square > Area=1^2=1 or (2^1/2)*(2^1/2)/2=1 Answer: C. I would really appreciate if a fault in my logic is pointed out. Statement 1: ABCD is either a square or a rhombus, so different areas. Insufficient. Statement 2: ABCD is a parallelogram with equal diagonals, so cannot be a rhombus. Possibly a rectangle or a square. Insufficient. 1+2. It must be a square. Answer C




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