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Finding the Fourth Proportional to 402.57, 603.92 and 128.69

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Solution

The fourth proportional to 402.57, 603.92 and 128.69 is: 193.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.57 : 603.92 = 128.69 : x
  2. Step 2: Convert to fraction form
    402.57/603.92 = 128.69/x
  3. Step 3: Cross multiply
    402.57x = 603.92 × 128.69
  4. Step 4: Simplify right side
    402.57x = 77,714.80
  5. Step 5: Solve for x
    x = 77,714.80/402.57
  6. Step 6: Final answer
    x = 193.05

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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.