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Geometry Difficulty 4.0 AIME Find the answer

Points A,B,C,DA,B,C,D and EE are located in 3-dimensional space with AB=BC=CD=DE=EA=2AB=BC=CD=DE=EA=2 and ABC=CDE=DEA=90o\angle ABC=\angle CDE=\angle DEA=90^o. The plane of ABC\triangle ABC is parallel to DE\overline{DE}. What is the area of BDE\triangle BDE?

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Solution

2007 AMC 12B Problem 25.png
Link to graph: https://www.math3d.org/pHFSD6vRi

Let A=(0,0,0)A=(0,0,0), and B=(2,0,0)B=(2,0,0). Since EA=2EA=2, we could let C=(2,0,2)C=(2,0,2), D=(2,2,2)D=(2,2,2), and E=(2,2,0)E=(2,2,0). Now to get back to AA we need another vertex F=(0,2,0)F=(0,2,0). Now if we look at this configuration as if it was two dimensions, we would see a square missing a side if we don't draw FAFA. Now we can bend these three sides into an equilateral triangle, and the coordinates change: A=(0,0,0)A=(0,0,0), B=(2,0,0)B=(2,0,0), C=(2,0,2)C=(2,0,2), D=(1,3,2)D=(1,\sqrt{3},2), and E=(1,3,0)E=(1,\sqrt{3},0). Checking for all the requirements, they are all satisfied. Now we find the area of triangle BDEBDE. The side lengths of this triangle are 2,2,222, 2, 2\sqrt{2}, which is an isosceles right triangle. Thus the area of it is 222=2(C)\frac{2\cdot2}{2}=2\Rightarrow \mathrm{(C)}.

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.