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Finding the Fourth Proportional to 420.78, 579.27 and 355.26

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Solution

The fourth proportional to 420.78, 579.27 and 355.26 is: 489.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.78 : 579.27 = 355.26 : x
  2. Step 2: Convert to fraction form
    420.78/579.27 = 355.26/x
  3. Step 3: Cross multiply
    420.78x = 579.27 × 355.26
  4. Step 4: Simplify right side
    420.78x = 205,791.46
  5. Step 5: Solve for x
    x = 205,791.46/420.78
  6. Step 6: Final answer
    x = 489.07

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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.