2. Perhatikan gambar berikut D с (4x - 3) cm A B (2x + 9) cm Diketahui perbandingan sisi AB dan BC adalah 5:3. Keliling persegi panjang tersebut adalah...
- Keliling persegi panjang = 48 cm
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Penjelasan dengan langkah-langkah :
Diketahui
- AB = (2x + 9)
- BC = (4x - 3)
- Perbandingan AB dan BC = 5 : 3
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Ditanya
- Keliling persegi panjang …?
[tex]\\[/tex]
Jawaban
Nilai x
[tex]\begin{array}{c}{\sf{AB : BC = 5 : 3}} \\ {\sf{(2x + 9) : (4x - 3) = 5 : 3 ~\qquad\qquad}} \\ {\sf{\frac{(2x + 9)}{(4x - 3)} = \frac{5}{3}}} \\ {\sf{~~~\quad3(2x + 9) = 5(4x - 3)}} \\ {\sf{~\qquad6x + 27 = 20x - 15}} \\ {\sf{~\qquad6x - 20x = -15 - 27}} \\ {\sf{~~\quad-14x = -42}} \\ {\sf{\quad\qquad x = \frac{-42}{-14}}} \\ {\sf{\qquad x = 3}}\end{array}[/tex]
[tex]\\[/tex]
AB = (2x + 9)
AB = (2(3) + 9)
AB = (6 + 9)
AB = 15 cm
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BC = (4x - 3)
BC = (4(3) - 3)
BC = (12 - 3)
BC = 9 cm
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Keliling = 2(AB + BC)
Keliling = 2(15 + 9)
Keliling = 2(24)
Keliling = 48 cm
[answer.2.content]
