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Finding the Fourth Proportional to 402.85, 604.04 and 128.80

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Solution

The fourth proportional to 402.85, 604.04 and 128.80 is: 193.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.85 : 604.04 = 128.80 : x
  2. Step 2: Convert to fraction form
    402.85/604.04 = 128.80/x
  3. Step 3: Cross multiply
    402.85x = 604.04 × 128.80
  4. Step 4: Simplify right side
    402.85x = 77,800.46
  5. Step 5: Solve for x
    x = 77,800.46/402.85
  6. Step 6: Final answer
    x = 193.12

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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.