Question

sebuah persegi panjang dengan panjang (3x-2) dan lebar (2x+1) jika kelilingnya 42cm, tentukan luasnya

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Answer 1

[tex]keliling = 2(p \times l) \\ 42 = 2(3x - 2 + 2x + 1) \\ 42 = 2(5x - 1) \\ 42 = 10x - 2 \\ 42 + 2 = 10x \\ 44 = 10x \\ x = \frac{44}{10} \\ x = 4.4[/tex]

[tex]panjang = 3x - 2 \\ = (3 \times 4.4) - 2 \\ = 13.2 - 2 \\ = 11.2cm[/tex]

[tex]lebar = 2x + 1 \\ = (2 \times 4.4) + 1 \\ = 8.8 + 1 \\ = 9.8cm \\ [/tex]

[tex]luas = p \times l \\ = 11.2 \times 9.8 \\ = 109,76cm {}^{2} [/tex]