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Re: In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
We have got one pair of parallel sides and one common point C. Therefore the triangles should be similar and the sides will have the same ratio.
Statement 1 alone is insufficient as it only gives us the ratio between BE and BC.
Statement 2 alone is insufficient as we can calculate DC but nothing about BC.
Combining the two statements, we can calculate the value of BC and hence the overall perimeter of DEC. Hence Option C is the correct answer.

Please correct me if my reasoning is wrong.
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Re: In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
nithinjohn wrote:
We have got one pair of parallel sides and one common point C. Therefore the triangles should be similar and the sides will have the same ratio.
Statement 1 alone is insufficient as it only gives us the ratio between BE and BC.
Statement 2 alone is insufficient as we can calculate DC but nothing about BC.
Combining the two statements, we can calculate the value of BC and hence the overall perimeter of DEC. Hence Option C is the correct answer.

Please correct me if my reasoning is wrong.


Hi,
As the position of D and E is unknown ,therefore, we can't say that triangles are similar and ratio of sides are equal .
Hence measure of side BC can't be determined

Hence ans (E)
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Re: In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
PKN wrote:
nithinjohn wrote:
We have got one pair of parallel sides and one common point C. Therefore the triangles should be similar and the sides will have the same ratio.
Statement 1 alone is insufficient as it only gives us the ratio between BE and BC.
Statement 2 alone is insufficient as we can calculate DC but nothing about BC.
Combining the two statements, we can calculate the value of BC and hence the overall perimeter of DEC. Hence Option C is the correct answer.

Please correct me if my reasoning is wrong.


Hi,
As the position of D and E is unknown ,therefore, we can't say that triangles are similar and ratio of sides are equal .
Hence measure of side BC can't be determined

Hence ans (E)


PKN-
It is given that AB is parallel to DE, so Angle BAC=Angle EDC & Angle ABC = Angle DEC also Angle DCE is common in both the triangles. So Triangle ABC should be similar to Triangle DEC by AAA similarity rule. Please correct if i am wrong.
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In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
AnupamKT wrote:
PKN wrote:
nithinjohn wrote:
We have got one pair of parallel sides and one common point C. Therefore the triangles should be similar and the sides will have the same ratio.
Statement 1 alone is insufficient as it only gives us the ratio between BE and BC.
Statement 2 alone is insufficient as we can calculate DC but nothing about BC.
Combining the two statements, we can calculate the value of BC and hence the overall perimeter of DEC. Hence Option C is the correct answer.

Please correct me if my reasoning is wrong.


Hi,
As the position of D and E is unknown ,therefore, we can't say that triangles are similar and ratio of sides are equal .
Hence measure of side BC can't be determined

Hence ans (E)


PKN-
It is given that AB is parallel to DE, so Angle BAC=Angle EDC & Angle ABC = Angle DEC also Angle DCE is common in both the triangles. So Triangle ABC should be similar to Triangle DEC by AAA similarity rule. Please correct if i am wrong.


Yes ,your reasoning is absolutely correct.

But what do you want to justify?

I'm not sure, in case u want to say we can determine perimeter by combing both statements using the triangle similarity property (ratio of sides are equal) then scale factor would play a vital role.Scale factor is not unique.Therefore,the sides of the triangle are not unique.Hence perimeter is not unique.

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Re: In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
Bunuel wrote:

In the figure above, if AB is parallel to DE and DE = 2, what is the perimeter of triangle DEC?

(1) BE is 5/7 of BC
(2) AC = 13 and AB = 7

Attachment:
image014.jpg


So this is my approach:

DE is given to us as 2.
Statement 1: BE is 5/7 of BC. Great. We have the ratio of sides and eventually the ~ triangles. Triangles are similar because 2 sides are parallel. One should be able to spot that. Apart from that you cannot find anything else.

Statement 2: AC is 13 and AB is 7. Firstly, I really don't need AB. So let's just ignore that. AC is 13. So we can split that in 2:5 ratio and find the sides Great. But what about BC? Is the triangle equilateral? Is it isosceles? I don't think so and we have no information to deduce that. So clearly not sufficient.

Combined, Well, doesn't really help.

IMO E.
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Re: In the figure above, if AB is parallel to DE and DE = 2, what is the [#permalink]
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