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Finding the Fourth Proportional to 871.20, 1,201.20 and 637.92

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Solution

The fourth proportional to 871.20, 1,201.20 and 637.92 is: 879.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.20 : 1,201.20 = 637.92 : x
  2. Step 2: Convert to fraction form
    871.20/1,201.20 = 637.92/x
  3. Step 3: Cross multiply
    871.20x = 1,201.20 × 637.92
  4. Step 4: Simplify right side
    871.20x = 766,269.50
  5. Step 5: Solve for x
    x = 766,269.50/871.20
  6. Step 6: Final answer
    x = 879.56

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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.