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Finding the Fourth Proportional to 420.45, 580.46 and 280.82

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Solution

The fourth proportional to 420.45, 580.46 and 280.82 is: 387.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.45 : 580.46 = 280.82 : x
  2. Step 2: Convert to fraction form
    420.45/580.46 = 280.82/x
  3. Step 3: Cross multiply
    420.45x = 580.46 × 280.82
  4. Step 4: Simplify right side
    420.45x = 163,000.47
  5. Step 5: Solve for x
    x = 163,000.47/420.45
  6. Step 6: Final answer
    x = 387.68

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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.