Bunuel

In the figure below, segments AB and CD represent two different ways the same steel girder can support wall EC. The length of AE is how much greater than the length of DE?
(1) The length of AB is 20 meters.
(2) The length of DE is 8 meters.
Kudos for a correct solution.Attachment:
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Recognize that the two triangles in the figure are both special right triangles. One is a 45:45:90 right triangle with sides in the ratio 1: 1: 2 and one is a 30:60:90 with sides in the ratio 1: 3 : 2. Also, recognize that their hypotenuses, AB and CD, are equal because they represent the same steel girder. Given these valuable tidbits of information, all you need is the length of one side of one of the triangles to discover all sides of both triangles. When you know the length of one side, you can solve for the length of its hypotenuse, which is the same length as the hypotenuse of the other triangle. Then you solve for the other side lengths and find the requested difference between AE and DE.
Statement (1) gives you the length of AB, so you can solve for AE. Plus, the length of AB is also the length of CD, because they represent the same girder. You can use the length of CD to solve for DE and then find the difference between AE and DE. Statement (1) is sufficient to answer the question, so the answer is either A or D.
Statement (2) gives you the same valuable information as statement (1). You know the length of DE, so you can solve for CD. You know the length of CD is the same as the length of AB, so you can use that information to solve for AE. Then you can find the difference between AE and DE. Statement (2) is also sufficient, so the answer can’t be A.
Choose D.