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Finding the Fourth Proportional to 385.89, 578.90 and 142.35

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Solution

The fourth proportional to 385.89, 578.90 and 142.35 is: 213.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.89 : 578.90 = 142.35 : x
  2. Step 2: Convert to fraction form
    385.89/578.90 = 142.35/x
  3. Step 3: Cross multiply
    385.89x = 578.90 × 142.35
  4. Step 4: Simplify right side
    385.89x = 82,406.42
  5. Step 5: Solve for x
    x = 82,406.42/385.89
  6. Step 6: Final answer
    x = 213.55

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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.