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Finding the Fourth Proportional to 258.47, 387.69 and 219.86

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Solution

The fourth proportional to 258.47, 387.69 and 219.86 is: 329.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.47 : 387.69 = 219.86 : x
  2. Step 2: Convert to fraction form
    258.47/387.69 = 219.86/x
  3. Step 3: Cross multiply
    258.47x = 387.69 × 219.86
  4. Step 4: Simplify right side
    258.47x = 85,235.58
  5. Step 5: Solve for x
    x = 85,235.58/258.47
  6. Step 6: Final answer
    x = 329.78

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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.