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Finding the Fourth Proportional to 611.20, 915.18 and 321.76

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Solution

The fourth proportional to 611.20, 915.18 and 321.76 is: 481.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.20 : 915.18 = 321.76 : x
  2. Step 2: Convert to fraction form
    611.20/915.18 = 321.76/x
  3. Step 3: Cross multiply
    611.20x = 915.18 × 321.76
  4. Step 4: Simplify right side
    611.20x = 294,468.32
  5. Step 5: Solve for x
    x = 294,468.32/611.20
  6. Step 6: Final answer
    x = 481.79

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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.