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Finding the Fourth Proportional to 641.64, 885.12 and 392.76

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Solution

The fourth proportional to 641.64, 885.12 and 392.76 is: 541.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.64 : 885.12 = 392.76 : x
  2. Step 2: Convert to fraction form
    641.64/885.12 = 392.76/x
  3. Step 3: Cross multiply
    641.64x = 885.12 × 392.76
  4. Step 4: Simplify right side
    641.64x = 347,639.73
  5. Step 5: Solve for x
    x = 347,639.73/641.64
  6. Step 6: Final answer
    x = 541.80

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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.