AB = 12
BC = 8
cos B = 30°
AC?
Jawab:
Nilai AC adalah [tex]\bf4\sqrt{13-6\sqrt{3}\,}[/tex].
Penjelasan dengan langkah-langkah
Diketahui:Pada segitiga ABC:AB = 12 cm, BC = 8 cm, ∠B = 30°.
Untuk mencari panjang AC, kita dapat menggunakan aturan cosinus.
[tex]\begin{aligned}AC^2&=AB^2+BC^2-2\cdot AB\cdot BC\cdot\cos(\angle{B})\\&=12^2+8^2-2\cdot12\cdot8\cdot\cos(30^\circ)\\&=144+64-\cancel{2}\cdot96\cdot\frac{1}{\cancel{2}}\sqrt{3}\\&=208-96\sqrt{3}\\&=16\left(13-6\sqrt{3}\right)\\&=4^2\left(13-6\sqrt{3}\right)\\AC&=\sqrt{4^2\left(13-6\sqrt{3}\right)}\\\therefore\ AC&=\bf4\sqrt{13-6\sqrt{3}}\end{aligned}[/tex]
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Verified answer
Diket:
AB = 12
BC = 8
cos B = 30°
Ditanya:
AC?
Jawab:
AC = √(AB^2 + BC^2 - 2 * AB * BC * cos B)
= √(12^2 + 8^2 - 2 * 12 * 8 * cos 30°)
= √(144 + 64 - 192 * (√3 / 2))
= √(208 - 192 * (√3 / 2))
Nilai AC adalah [tex]\bf4\sqrt{13-6\sqrt{3}\,}[/tex].
Penjelasan dengan langkah-langkah
Diketahui:
Pada segitiga ABC:
AB = 12 cm, BC = 8 cm, ∠B = 30°.
Untuk mencari panjang AC, kita dapat menggunakan aturan cosinus.
[tex]\begin{aligned}AC^2&=AB^2+BC^2-2\cdot AB\cdot BC\cdot\cos(\angle{B})\\&=12^2+8^2-2\cdot12\cdot8\cdot\cos(30^\circ)\\&=144+64-\cancel{2}\cdot96\cdot\frac{1}{\cancel{2}}\sqrt{3}\\&=208-96\sqrt{3}\\&=16\left(13-6\sqrt{3}\right)\\&=4^2\left(13-6\sqrt{3}\right)\\AC&=\sqrt{4^2\left(13-6\sqrt{3}\right)}\\\therefore\ AC&=\bf4\sqrt{13-6\sqrt{3}}\end{aligned}[/tex]