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Finding the Fourth Proportional to 259.78, 388.60 and 213.61

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Solution

The fourth proportional to 259.78, 388.60 and 213.61 is: 319.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.78 : 388.60 = 213.61 : x
  2. Step 2: Convert to fraction form
    259.78/388.60 = 213.61/x
  3. Step 3: Cross multiply
    259.78x = 388.60 × 213.61
  4. Step 4: Simplify right side
    259.78x = 83,008.85
  5. Step 5: Solve for x
    x = 83,008.85/259.78
  6. Step 6: Final answer
    x = 319.54

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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.