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Finding the Fourth Proportional to 402.12, 603.17 and 128.21

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Solution

The fourth proportional to 402.12, 603.17 and 128.21 is: 192.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.12 : 603.17 = 128.21 : x
  2. Step 2: Convert to fraction form
    402.12/603.17 = 128.21/x
  3. Step 3: Cross multiply
    402.12x = 603.17 × 128.21
  4. Step 4: Simplify right side
    402.12x = 77,330.62
  5. Step 5: Solve for x
    x = 77,330.62/402.12
  6. Step 6: Final answer
    x = 192.31

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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.