Jika DC=EO=EB , maka berapakah panjang BC.....

• BC = √53,8
• BC = 7,335

Penjelasan dengan langkah-langkah:

misal CD = EO = EB = x

• x/6 X (5+x)/x X x/4 = 1
• x² (5+x) / 24x = 1
• 5x² +x³ / 24x = 1
• x² + 5x - 24 = 0
• (x -3) (x +8) = 0
• x1 = 3
• x2 = -8

Diambil x positif , x= 3

• AC= 6+3= 9
• AB= 5+3= 8
• EC= 4+3= 7
• Cos A = (AE² + AC² - EC²)/(2(AE×AC))
• Cos A = 5² + 9² - 7²)/(2(5×9))
• Cos A = (25 + 81 - 49)/(2×45)
• Cos A = (106-49)/90
• Cos A = 57/90
• Cos A = 19/30

BC² = AB² + AC² - 2(AB×AC)cos A

• BC²  = (8² + 9² - 2(8×9)cos A
• BC²  = 64+81 - 2(72)cos A
• BC²  = 145 - 144(19/30)
• BC²  = 145 - 2736/30
• BC²  = (4350 - 2736)/30
• BC²  = 1614/30
• BC²  = 269/5
• BC²  = 53⅘
• BC = √53,8
• BC = 7,335. ✓

Pelajari Lebih lanjut

Pelajari lebih lanjut materi tentang 5 contoh soal beserta pembahasanya tentang geometri yomemimo.com/tugas/6182821

#BelajarBersamaBrainly#SPJ1