Find the altitude of an equilateral triangle of side 8 cm.


Let LMN be an equilateral triangle of side 8 cm

LM = MN = NL = 8 cm. (all sides of an equilateral triangle is equal)



Draw altitude LD which is perpendicular to MN.


Then, D is the mid-point of MN.


MD = ND = 1/2


MN = 8/2 = 4 cm


Now, by Pythagoras theorem


LM2 = LD2 + MD2


(8)2 = LD2 + (4)2


64 = LD2 + 16


LD = √48 = 4√3 cm.


Hence, altitude of an equilateral triangle is 4√3 cm.


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