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Finding the Fourth Proportional to 385.78, 578.38 and 142.26

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Solution

The fourth proportional to 385.78, 578.38 and 142.26 is: 213.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.78 : 578.38 = 142.26 : x
  2. Step 2: Convert to fraction form
    385.78/578.38 = 142.26/x
  3. Step 3: Cross multiply
    385.78x = 578.38 × 142.26
  4. Step 4: Simplify right side
    385.78x = 82,276.74
  5. Step 5: Solve for x
    x = 82,276.74/385.78
  6. Step 6: Final answer
    x = 213.28

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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.