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Introduction To Trigonometry

Question
CBSEENMA10006981

Check whether (5, – 2), (6, 4) and (7, – 2) are the vertices of an isosceles triangle.

Solution
Let the given points be A(5, -2), B(6, 4) and C(7, -2). Then
AB space equals space square root of open parentheses 6 minus 5 close parentheses squared plus left curly bracket 4 minus left parenthesis negative 2 right parenthesis right curly bracket squared end root
space space space space space equals space square root of open parentheses 1 close parentheses squared plus left parenthesis 6 right parenthesis squared end root equals square root of 1 plus 36 end root
space space space space space equals square root of 37
BC space equals space square root of open parentheses 7 minus 6 close parentheses squared plus left parenthesis negative 2 minus 4 right parenthesis squared end root
space space space space space space equals space square root of open parentheses 1 close parentheses squared plus left parenthesis negative 6 right parenthesis squared end root
space space space space space space space equals space square root of 1 plus 36 end root equals 37
Since      AB = BC
Therefore, ABC is an isosceles triangle.