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Finding the Fourth Proportional to 825.78, 1,239.12 and 338.79

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Solution

The fourth proportional to 825.78, 1,239.12 and 338.79 is: 508.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.78 : 1,239.12 = 338.79 : x
  2. Step 2: Convert to fraction form
    825.78/1,239.12 = 338.79/x
  3. Step 3: Cross multiply
    825.78x = 1,239.12 × 338.79
  4. Step 4: Simplify right side
    825.78x = 419,801.46
  5. Step 5: Solve for x
    x = 419,801.46/825.78
  6. Step 6: Final answer
    x = 508.37

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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.