In an isosceles triangle ABC AB = BC = 7cm, AC = 6cm. Find the length of the height BD.

Since triangle ABC, by condition, is isosceles, then its height BD is also its median and bisector, then triangles ABD and СВD are rectangular, and AD = CD = AC / 2 = 6/2 = 3 cm.

Then, in a right-angled triangle ВСD, according to the Pythagorean theorem, we determine the length of the leg ВD.

ВD ^ 2 = ВС ^ 2 – СD ^ 2 = 7 ^ 2 – 3 ^ 2 = 49 – 9 = 40.

ВM = √40 = 2 * √10 cm.

Answer: The length of the height BD is 2 * √10 cm.



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