

InterviewSolution
1. |
Triangle DEF is right-angled at E, EG is perpendicular to DF and GH is perpendicular to EF. Prove that:1) GH2=EH.HF2) EG2=DG.GF |
Answer» Given :-
To Prove :-
Solution :- Let us assume that, ∠F = x° . Than, → ∠FEG = (90 - x°) { As, EG ⟂ DF .} Also, in ∆GHF, → ∠HGF = (90 - x°) { As, GH ⟂ EF. } Now, in ∆GHE and ∆FHG, we have, → ∠GHE = ∠FHG (90°) → ∠GEH = ∠FGH (90 - x°) So, → ∆GHE ~ ∆FHG . (By AA similarity) . Therefore, → GH/EH = HF/GH (By CPCT) → GH² = EH * HF (Proved). ________________________________________________________________________ Now, Similarly, → ∠EFD = x° → ∠EDG = (90 - x°) → ∠FEG = (90 - x°) Now, in ∆EGF and ∆DGE, → ∠EGF = ∠DGE. (90°) → ∠FEG = ∠EDG. (90 - x°) So, → ∆EGF ~ ∆DGE .(By AA Similarity.) Therefore, → EG / GF = DG / EG (By CPCT. ) Hence, → EG² = DG * GF. (Proved.) |
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