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Finding the Fourth Proportional to 431.20, 642.83 and 411.76

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Solution

The fourth proportional to 431.20, 642.83 and 411.76 is: 613.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.20 : 642.83 = 411.76 : x
  2. Step 2: Convert to fraction form
    431.20/642.83 = 411.76/x
  3. Step 3: Cross multiply
    431.20x = 642.83 × 411.76
  4. Step 4: Simplify right side
    431.20x = 264,691.68
  5. Step 5: Solve for x
    x = 264,691.68/431.20
  6. Step 6: Final answer
    x = 613.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.