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Finding the Fourth Proportional to 420.17, 580.07 and 280.47

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Solution

The fourth proportional to 420.17, 580.07 and 280.47 is: 387.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.17 : 580.07 = 280.47 : x
  2. Step 2: Convert to fraction form
    420.17/580.07 = 280.47/x
  3. Step 3: Cross multiply
    420.17x = 580.07 × 280.47
  4. Step 4: Simplify right side
    420.17x = 162,690.83
  5. Step 5: Solve for x
    x = 162,690.83/420.17
  6. Step 6: Final answer
    x = 387.21

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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.