∠ A = 30^° , ∠ C = 120^° dan c = 6, hitunglah sisi a dan b
Jawaban:
sudut a = 30°
sudut c = 120°
sudut b = ?
• Cari sudut b
= 180 – 120 – 30
= 30°
• Cari sisi a
a/Sin 30° = 6/Sin 120°
a/1/2 = 6/√3/2
2a = 12/√3
a = 6/√3 — rasionalkan
a = 6/√3 x √3/√3
a = 6√3 / 3
a = 2√3
• Cari sisi b
b = √6² + (2√3)² – 2 x 6 x 2√3 x Cos 30°
b = √36 + 12 – 2 x 6 x 2√3 x √3/2
b = √48 – 6 x 2√3 x √3
b = √48 – 6 x 6
b = √48 – 36
b = √12