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त्रिभुज

Question
CBSEHHIMAH10010111

ABC और BDE दो समबाहु त्रिभुज इस प्रकार हैं कि D भुजा BC का मध्य-बंदु है। त्रिभुजों ABC और BDE के क्षेत्रफलों का अनुपात है:
  • 2:1

  • 1:2

  • 4:1

  • 1:4

Solution

∆ABC और ∆BDE दोनों समबाहु त्रिभुज हैं।
∴    ∆ABC ~ ∆BDE
∴    fraction numerator ar left parenthesis increment ABC right parenthesis over denominator ar left parenthesis increment BDE right parenthesis end fraction equals AB squared over BD squared
rightwards double arrow  fraction numerator ar left parenthesis increment ABC right parenthesis over denominator ar left parenthesis increment BDE right parenthesis end fraction space equals space open parentheses BC over BD close parentheses squared
space space space space space space space space space space space space space space space space left square bracket because space AB space equals space BC space equals space CA right square bracket
rightwards double arrow space space space fraction numerator ar left parenthesis increment ABC right parenthesis over denominator ar left parenthesis increment BDE right parenthesis end fraction space equals space open parentheses fraction numerator 2 BD over denominator BD end fraction close parentheses squared
rightwards double arrow space space space fraction numerator ar left parenthesis increment ABC right parenthesis over denominator ar left parenthesis increment BDE right parenthesis end fraction space equals space 4 over 1
अत: C(4:1) सही उत्तर है