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Finding the Fourth Proportional to 831, 1,245.60 and 397.20

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Solution

The fourth proportional to 831, 1,245.60 and 397.20 is: 595.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    831 : 1,245.60 = 397.20 : x
  2. Step 2: Convert to fraction form
    831/1,245.60 = 397.20/x
  3. Step 3: Cross multiply
    831x = 1,245.60 × 397.20
  4. Step 4: Simplify right side
    831x = 494,752.32
  5. Step 5: Solve for x
    x = 494,752.32/831
  6. Step 6: Final answer
    x = 595.37

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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.