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Finding the Fourth Proportional to 871.18, 1,202.21 and 478.20

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Solution

The fourth proportional to 871.18, 1,202.21 and 478.20 is: 659.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.18 : 1,202.21 = 478.20 : x
  2. Step 2: Convert to fraction form
    871.18/1,202.21 = 478.20/x
  3. Step 3: Cross multiply
    871.18x = 1,202.21 × 478.20
  4. Step 4: Simplify right side
    871.18x = 574,896.82
  5. Step 5: Solve for x
    x = 574,896.82/871.18
  6. Step 6: Final answer
    x = 659.91

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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.