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Finding the Fourth Proportional to 429.78, 645.48 and 321.24

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Solution

The fourth proportional to 429.78, 645.48 and 321.24 is: 482.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.78 : 645.48 = 321.24 : x
  2. Step 2: Convert to fraction form
    429.78/645.48 = 321.24/x
  3. Step 3: Cross multiply
    429.78x = 645.48 × 321.24
  4. Step 4: Simplify right side
    429.78x = 207,354.00
  5. Step 5: Solve for x
    x = 207,354.00/429.78
  6. Step 6: Final answer
    x = 482.47

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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.