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Finding the Fourth Proportional to 339.78, 509.78 and 123.38

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Solution

The fourth proportional to 339.78, 509.78 and 123.38 is: 185.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    339.78 : 509.78 = 123.38 : x
  2. Step 2: Convert to fraction form
    339.78/509.78 = 123.38/x
  3. Step 3: Cross multiply
    339.78x = 509.78 × 123.38
  4. Step 4: Simplify right side
    339.78x = 62,896.66
  5. Step 5: Solve for x
    x = 62,896.66/339.78
  6. Step 6: Final answer
    x = 185.11

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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.