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Finding the Fourth Proportional to 258.39, 385.43 and 219.78

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Solution

The fourth proportional to 258.39, 385.43 and 219.78 is: 327.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.39 : 385.43 = 219.78 : x
  2. Step 2: Convert to fraction form
    258.39/385.43 = 219.78/x
  3. Step 3: Cross multiply
    258.39x = 385.43 × 219.78
  4. Step 4: Simplify right side
    258.39x = 84,708.71
  5. Step 5: Solve for x
    x = 84,708.71/258.39
  6. Step 6: Final answer
    x = 327.83

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.