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Finding the Fourth Proportional to 421.47, 580.79 and 355.09

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Solution

The fourth proportional to 421.47, 580.79 and 355.09 is: 489.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.47 : 580.79 = 355.09 : x
  2. Step 2: Convert to fraction form
    421.47/580.79 = 355.09/x
  3. Step 3: Cross multiply
    421.47x = 580.79 × 355.09
  4. Step 4: Simplify right side
    421.47x = 206,229.82
  5. Step 5: Solve for x
    x = 206,229.82/421.47
  6. Step 6: Final answer
    x = 489.31

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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.