panjang EF adalah....

[tex]ef = \frac{(cf \times ab) + (fb \times dc)}{cf + fb} \\ ef = \frac{(9 \times 12) + (6 \times 20)}{9 + 6} \\ ef = \frac{108 + 120}{15} \\ ef = \frac{228}{15} \\ ef = 15.2 \: cm[/tex]


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