Question

in triangle ABC, AB=AC. side BC is produced to D. prove that (AC squre-AC sure) = BD into CD
${ad}^{2} - {ac}^{2} = bd \times cd$
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Answer 1

Since, ABC is an isosceles triangle and AE is the altitude and we know that the altitude is also the median of the isosceles triangle.  So, BE = CE  And DE+CE=DE+BE=BD