jika panjang diagonal km = 12√3 cm luas klmn =

Bab Trigonometri
Matematika SMA Kelas X

sudut NKM = 1/2 x 60° = 30°

KM/sin N = NM/sin sudut NKM
NM = 12√3 . sin 30° : sin 120°
NM = (12√3 . 1/2) : 1/2√3
NM = 12 cm

titik potong antara LM dan KM adalah titik O

MO = 1/2 x KM
MO = 1/2 x 12√3
MO = 6√3 cm

NO = √(NM² - MO²)
NO = √(12² - (6√3)²)
NO = √(144 - 108)
NO = √36
NO = 6 cm

NL = 2 x NO
NL = 2 x 6
NL = 12 cm

luas belah ketupat KLMN
= 1/2 x d1 x d2
= 1/2 x KM x NL
= 1/2 x 12√3 x 12
= 72√3 cm²

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