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back to boardInstruction how to solve. Check (AB,CD)==0 (orthogonality). Check (AB, CD, DA) ==0 (planarity). Check AD>AC>AB, AC>BC, BD>BC (order). Check whether the projections to XY, YZ, XZ craddle each other continuations. It is sufficient to check only the projections to XY plane to get Accepted verdict. Re: Instruction how to solve. Sounds too complex. If we replace C, D with their orthogonal projection on AB, then all steps except first collapse to only one step (check D = C*a, a > 1). Still too complex, though. Over 20 lines in Python. There should be more simple solution... Edited by author 26.12.2017 04:30 Re: Instruction how to solve. Posted by ASK 15 Mar 2018 19:04 No lengths or projections XY, etc. Using scalar product (sp) and triple product (tp) it is at most five conditions: sp(ab,cd) == 0 and tp(ab,bc,cd) == 0 and # ⟂ and planar sp(ab,bc) >= 0 and # C after B sp(cd,bc) >= 0 and # BC goes in direction of CD sp(cd,bd) >= sp(cd,bc) # D after C |
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