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Finding the Fourth Proportional to 641.64, 885.30 and 392.88

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Solution

The fourth proportional to 641.64, 885.30 and 392.88 is: 542.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.64 : 885.30 = 392.88 : x
  2. Step 2: Convert to fraction form
    641.64/885.30 = 392.88/x
  3. Step 3: Cross multiply
    641.64x = 885.30 × 392.88
  4. Step 4: Simplify right side
    641.64x = 347,816.66
  5. Step 5: Solve for x
    x = 347,816.66/641.64
  6. Step 6: Final answer
    x = 542.07

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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.