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Finding the Fourth Proportional to 391.20, 585.48 and 281.20

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Solution

The fourth proportional to 391.20, 585.48 and 281.20 is: 420.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.20 : 585.48 = 281.20 : x
  2. Step 2: Convert to fraction form
    391.20/585.48 = 281.20/x
  3. Step 3: Cross multiply
    391.20x = 585.48 × 281.20
  4. Step 4: Simplify right side
    391.20x = 164,636.98
  5. Step 5: Solve for x
    x = 164,636.98/391.20
  6. Step 6: Final answer
    x = 420.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.