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Finding the Fourth Proportional to 557.78, 769.78 and 309.12

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Solution

The fourth proportional to 557.78, 769.78 and 309.12 is: 426.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    557.78 : 769.78 = 309.12 : x
  2. Step 2: Convert to fraction form
    557.78/769.78 = 309.12/x
  3. Step 3: Cross multiply
    557.78x = 769.78 × 309.12
  4. Step 4: Simplify right side
    557.78x = 237,954.39
  5. Step 5: Solve for x
    x = 237,954.39/557.78
  6. Step 6: Final answer
    x = 426.61

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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.