# math

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one side of an equilateral triangle is 42cm.find the length of an altitude of the triangle.

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You can use the Pythagorean Theorem:

a^2 + b^2 = c^2

a^2 + 21^2 = 42^2

a^2 + 441 = 1764

a^2 = 1764 - 441

a^2 = 1323

a = 36.37 cm

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