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Finding the Fourth Proportional to 385.63, 578.61 and 138.87

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Solution

The fourth proportional to 385.63, 578.61 and 138.87 is: 208.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.63 : 578.61 = 138.87 : x
  2. Step 2: Convert to fraction form
    385.63/578.61 = 138.87/x
  3. Step 3: Cross multiply
    385.63x = 578.61 × 138.87
  4. Step 4: Simplify right side
    385.63x = 80,350.17
  5. Step 5: Solve for x
    x = 80,350.17/385.63
  6. Step 6: Final answer
    x = 208.36

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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.