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Finding the Fourth Proportional to 385.38, 578.14 and 128.88

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Solution

The fourth proportional to 385.38, 578.14 and 128.88 is: 193.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.38 : 578.14 = 128.88 : x
  2. Step 2: Convert to fraction form
    385.38/578.14 = 128.88/x
  3. Step 3: Cross multiply
    385.38x = 578.14 × 128.88
  4. Step 4: Simplify right side
    385.38x = 74,510.68
  5. Step 5: Solve for x
    x = 74,510.68/385.38
  6. Step 6: Final answer
    x = 193.34

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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.