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Finding the Fourth Proportional to 354.78, 489.38 and 280.08

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Solution

The fourth proportional to 354.78, 489.38 and 280.08 is: 386.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.78 : 489.38 = 280.08 : x
  2. Step 2: Convert to fraction form
    354.78/489.38 = 280.08/x
  3. Step 3: Cross multiply
    354.78x = 489.38 × 280.08
  4. Step 4: Simplify right side
    354.78x = 137,064.15
  5. Step 5: Solve for x
    x = 137,064.15/354.78
  6. Step 6: Final answer
    x = 386.34

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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.