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Finding the Fourth Proportional to 917.28, 1,375.11 and 339.78

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Solution

The fourth proportional to 917.28, 1,375.11 and 339.78 is: 509.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    917.28 : 1,375.11 = 339.78 : x
  2. Step 2: Convert to fraction form
    917.28/1,375.11 = 339.78/x
  3. Step 3: Cross multiply
    917.28x = 1,375.11 × 339.78
  4. Step 4: Simplify right side
    917.28x = 467,234.88
  5. Step 5: Solve for x
    x = 467,234.88/917.28
  6. Step 6: Final answer
    x = 509.37

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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.