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Finding the Fourth Proportional to 385.91, 578.82 and 139.09

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Solution

The fourth proportional to 385.91, 578.82 and 139.09 is: 208.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.91 : 578.82 = 139.09 : x
  2. Step 2: Convert to fraction form
    385.91/578.82 = 139.09/x
  3. Step 3: Cross multiply
    385.91x = 578.82 × 139.09
  4. Step 4: Simplify right side
    385.91x = 80,509.47
  5. Step 5: Solve for x
    x = 80,509.47/385.91
  6. Step 6: Final answer
    x = 208.62

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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.