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Finding the Fourth Proportional to 478.92, 661.20 and 321.78

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Solution

The fourth proportional to 478.92, 661.20 and 321.78 is: 444.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.92 : 661.20 = 321.78 : x
  2. Step 2: Convert to fraction form
    478.92/661.20 = 321.78/x
  3. Step 3: Cross multiply
    478.92x = 661.20 × 321.78
  4. Step 4: Simplify right side
    478.92x = 212,760.94
  5. Step 5: Solve for x
    x = 212,760.94/478.92
  6. Step 6: Final answer
    x = 444.25

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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.