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Question
Find the area of an equilateral triangle having perimeter of 18cm.
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Solution
Find side length
`"Side" = "Perimeter"/3 = 18/3 = 6 cm`
`"Area" = sqrt3/4 xx a^2`
a = side length.
`Area = sqrt3/4 xx (6^2) = sqrt3/4 xx 36 = 9sqrt3 cm^2`
`9sqrt3 = 9 xx 1.732 = 15.588 cm^2`
`Area = 9sqrt3 cm^2 = 15.6 cm^2`
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