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Finding the Fourth Proportional to 641.50, 885.20 and 392.70

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Solution

The fourth proportional to 641.50, 885.20 and 392.70 is: 541.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.50 : 885.20 = 392.70 : x
  2. Step 2: Convert to fraction form
    641.50/885.20 = 392.70/x
  3. Step 3: Cross multiply
    641.50x = 885.20 × 392.70
  4. Step 4: Simplify right side
    641.50x = 347,618.04
  5. Step 5: Solve for x
    x = 347,618.04/641.50
  6. Step 6: Final answer
    x = 541.88

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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.