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Finding the Fourth Proportional to 638.40, 956.40 and 329.20

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Solution

The fourth proportional to 638.40, 956.40 and 329.20 is: 493.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.40 : 956.40 = 329.20 : x
  2. Step 2: Convert to fraction form
    638.40/956.40 = 329.20/x
  3. Step 3: Cross multiply
    638.40x = 956.40 × 329.20
  4. Step 4: Simplify right side
    638.40x = 314,846.88
  5. Step 5: Solve for x
    x = 314,846.88/638.40
  6. Step 6: Final answer
    x = 493.18

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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.