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ira [324]
4 years ago
12

Find the missing number ___:7 = 12:21a.14b.12c.4d.3

Mathematics
1 answer:
Novay_Z [31]4 years ago
6 0
x:7=12:21\to\dfrac{x}{7}=\dfrac{12}{21}\ \ \ |cross\ multiply\\\\21x=7\cdot12\\21x=84\ \ \ |divide\ both\ sides\ by\ 21\\\boxed{x=4}\\\\Other\ method:\\\dfrac{x}{7}=\dfrac{12}{21}\\\\21:7=\boxed3\to12:\boxed3=4\\\\\boxed{\frac{4}{7}=\frac{12}{21}\to4:7=12:21}
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3 years ago
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