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Finding the Fourth Proportional to 458.76, 687.79 and 321.40

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Solution

The fourth proportional to 458.76, 687.79 and 321.40 is: 481.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.76 : 687.79 = 321.40 : x
  2. Step 2: Convert to fraction form
    458.76/687.79 = 321.40/x
  3. Step 3: Cross multiply
    458.76x = 687.79 × 321.40
  4. Step 4: Simplify right side
    458.76x = 221,056.97
  5. Step 5: Solve for x
    x = 221,056.97/458.76
  6. Step 6: Final answer
    x = 481.85

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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.