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Finding the Fourth Proportional to 420.07, 579.48 and 391.90

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Solution

The fourth proportional to 420.07, 579.48 and 391.90 is: 540.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.07 : 579.48 = 391.90 : x
  2. Step 2: Convert to fraction form
    420.07/579.48 = 391.90/x
  3. Step 3: Cross multiply
    420.07x = 579.48 × 391.90
  4. Step 4: Simplify right side
    420.07x = 227,098.21
  5. Step 5: Solve for x
    x = 227,098.21/420.07
  6. Step 6: Final answer
    x = 540.62

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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.