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Finding the Fourth Proportional to 385.70, 578.46 and 129.20

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Solution

The fourth proportional to 385.70, 578.46 and 129.20 is: 193.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.70 : 578.46 = 129.20 : x
  2. Step 2: Convert to fraction form
    385.70/578.46 = 129.20/x
  3. Step 3: Cross multiply
    385.70x = 578.46 × 129.20
  4. Step 4: Simplify right side
    385.70x = 74,737.03
  5. Step 5: Solve for x
    x = 74,737.03/385.70
  6. Step 6: Final answer
    x = 193.77

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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.