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Finding the Fourth Proportional to 871.20, 1,202.21 and 478.19

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Solution

The fourth proportional to 871.20, 1,202.21 and 478.19 is: 659.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.20 : 1,202.21 = 478.19 : x
  2. Step 2: Convert to fraction form
    871.20/1,202.21 = 478.19/x
  3. Step 3: Cross multiply
    871.20x = 1,202.21 × 478.19
  4. Step 4: Simplify right side
    871.20x = 574,892.15
  5. Step 5: Solve for x
    x = 574,892.15/871.20
  6. Step 6: Final answer
    x = 659.89

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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.