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Finding the Fourth Proportional to 402.64, 603.86 and 128.70

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Solution

The fourth proportional to 402.64, 603.86 and 128.70 is: 193.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.64 : 603.86 = 128.70 : x
  2. Step 2: Convert to fraction form
    402.64/603.86 = 128.70/x
  3. Step 3: Cross multiply
    402.64x = 603.86 × 128.70
  4. Step 4: Simplify right side
    402.64x = 77,716.78
  5. Step 5: Solve for x
    x = 77,716.78/402.64
  6. Step 6: Final answer
    x = 193.02

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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.