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Finding the Fourth Proportional to 668, 921.92 and 392

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Solution

The fourth proportional to 668, 921.92 and 392 is: 541.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    668 : 921.92 = 392 : x
  2. Step 2: Convert to fraction form
    668/921.92 = 392/x
  3. Step 3: Cross multiply
    668x = 921.92 × 392
  4. Step 4: Simplify right side
    668x = 361,392.64
  5. Step 5: Solve for x
    x = 361,392.64/668
  6. Step 6: Final answer
    x = 541.01

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.