tolong ya.. secepatnya
Matematika
nurull32
Pertanyaan
tolong ya.. secepatnya
1 Jawaban
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1. Jawaban whongaliem
1) dari data gambar diperoleh
∠ B = 90°
∠ C = 180° - 90° - 30°
= 60°
2) ∠ A = 180° - 60° - 45°
= 75°
sin 75° = sin (45 + 30)°
= sin 45° .cos 30° + cos 45° .sin 30°
= 1/2 √2 . 1/2 √3 + 1/2 √2 . 1/2
= 1/4√6 + 1/4√2
= 1/4 (√6 + √2)
a / sin A = c / sin c
a / sin 75° = 16 / sin 45°
a / 1/4(√6 + √2) = 16 / 1/2√2
1/2 √2 . a = 16 . 1/4 (√6 + √2) ..... kalikan dengan 2
√2 . a = 6 (√6 + √2)
a = 6 (√6 + √2) / √2
a = 3 (√6 + √2) √2
a = 3 (√12 + 2)
a = 3√12 + 6
a = 6√3 + 6
a = 6 (1,73) + 6
a = 10,38 + 6
a = 16,38 cm
b / sin B = c / sin C
b / sin 60° = 16 / sin 45°
b / (1/2√3) = 16 / (1/2√2)
b / √3 = 16 / √2
√2 . b = 16√3
b = 16√3 / √2
b = 8√6
b = 8 .(2,45)
b = 19,6 cm