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Finding the Fourth Proportional to 687.61, 948.84 and 392.86

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Solution

The fourth proportional to 687.61, 948.84 and 392.86 is: 542.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.61 : 948.84 = 392.86 : x
  2. Step 2: Convert to fraction form
    687.61/948.84 = 392.86/x
  3. Step 3: Cross multiply
    687.61x = 948.84 × 392.86
  4. Step 4: Simplify right side
    687.61x = 372,761.28
  5. Step 5: Solve for x
    x = 372,761.28/687.61
  6. Step 6: Final answer
    x = 542.11

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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.