Arithmeticeasy · Past Paper
If $x, 4, 9, 12$ are in proportion, find $x$.
A3
B2.5
C3.5
D4
✓ Correct Answer: A — 3
If a, b, c, d are in proportion, a/b = c/d. So x/4 = 9/12. x = (9*4)/12 = 36/12 = 3.
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