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Finding the Fourth Proportional to 938.76, 1,407.86 and 280.61

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Solution

The fourth proportional to 938.76, 1,407.86 and 280.61 is: 420.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.76 : 1,407.86 = 280.61 : x
  2. Step 2: Convert to fraction form
    938.76/1,407.86 = 280.61/x
  3. Step 3: Cross multiply
    938.76x = 1,407.86 × 280.61
  4. Step 4: Simplify right side
    938.76x = 395,059.59
  5. Step 5: Solve for x
    x = 395,059.59/938.76
  6. Step 6: Final answer
    x = 420.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.