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Luas Segitiga

AB/AC = cos A
AB = AC . cos A
AB = 6. cos 30 = 6 ( 1/2 √ 3) 
AB = 3√3

AD/AB = cos 30
AD = AB. cos 30
AD = (3√3)( 1/2 √3) = 9/2

Luas Δ ABD = 1/2 (AB)(AD) sin A
L = 1/2 (3√3) (9/2) (sin 30)
L = 27/4 √ 3 (1/2)
L = (27/8) √3
L = 3³/₈ √3