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Finding the Fourth Proportional to 389.92, 585 and 280.48

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Solution

The fourth proportional to 389.92, 585 and 280.48 is: 420.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.92 : 585 = 280.48 : x
  2. Step 2: Convert to fraction form
    389.92/585 = 280.48/x
  3. Step 3: Cross multiply
    389.92x = 585 × 280.48
  4. Step 4: Simplify right side
    389.92x = 164,080.80
  5. Step 5: Solve for x
    x = 164,080.80/389.92
  6. Step 6: Final answer
    x = 420.81

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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.