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Finding the Fourth Proportional to 417.12, 625.78 and 128.56

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Solution

The fourth proportional to 417.12, 625.78 and 128.56 is: 192.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    417.12 : 625.78 = 128.56 : x
  2. Step 2: Convert to fraction form
    417.12/625.78 = 128.56/x
  3. Step 3: Cross multiply
    417.12x = 625.78 × 128.56
  4. Step 4: Simplify right side
    417.12x = 80,450.28
  5. Step 5: Solve for x
    x = 80,450.28/417.12
  6. Step 6: Final answer
    x = 192.87

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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.