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Finding the Fourth Proportional to 385.61, 578.42 and 142.08

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Solution

The fourth proportional to 385.61, 578.42 and 142.08 is: 213.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.61 : 578.42 = 142.08 : x
  2. Step 2: Convert to fraction form
    385.61/578.42 = 142.08/x
  3. Step 3: Cross multiply
    385.61x = 578.42 × 142.08
  4. Step 4: Simplify right side
    385.61x = 82,181.20
  5. Step 5: Solve for x
    x = 82,181.20/385.61
  6. Step 6: Final answer
    x = 213.12

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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.