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Finding the Fourth Proportional to 871.20, 1,306.80 and 221.90

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Solution

The fourth proportional to 871.20, 1,306.80 and 221.90 is: 332.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.20 : 1,306.80 = 221.90 : x
  2. Step 2: Convert to fraction form
    871.20/1,306.80 = 221.90/x
  3. Step 3: Cross multiply
    871.20x = 1,306.80 × 221.90
  4. Step 4: Simplify right side
    871.20x = 289,972.39
  5. Step 5: Solve for x
    x = 289,972.39/871.20
  6. Step 6: Final answer
    x = 332.84

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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.