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Finding the Fourth Proportional to 354.90, 489.78 and 215.10

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Solution

The fourth proportional to 354.90, 489.78 and 215.10 is: 296.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.90 : 489.78 = 215.10 : x
  2. Step 2: Convert to fraction form
    354.90/489.78 = 215.10/x
  3. Step 3: Cross multiply
    354.90x = 489.78 × 215.10
  4. Step 4: Simplify right side
    354.90x = 105,351.68
  5. Step 5: Solve for x
    x = 105,351.68/354.90
  6. Step 6: Final answer
    x = 296.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.