Tolong bantu no 29?….
Jawaban Terkonfirmasi
∠ C = 180° - ∠ A - ∠ B
= 180° – 120° – 30°
= 30°
⇒ Δ ABC sama kaki ( AC = AB)
BC / sin A = AB / sin B
36 / sin 120° = AB / sin 30°
36 / (1/2)√3 = AB / 1/2 ……. kalikan 2
36 / √3 = AB
AB = 12√3 ⇒ AC = 12/√3
Luas = 1/2 . AB . AC . sin A
= 1/2 . 12√3 . 12√3 . sin 120°
= 216 . 1/2√3
= 108√3 cm²