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Finding the Fourth Proportional to 385.74, 578.70 and 142.28

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Solution

The fourth proportional to 385.74, 578.70 and 142.28 is: 213.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.74 : 578.70 = 142.28 : x
  2. Step 2: Convert to fraction form
    385.74/578.70 = 142.28/x
  3. Step 3: Cross multiply
    385.74x = 578.70 × 142.28
  4. Step 4: Simplify right side
    385.74x = 82,337.44
  5. Step 5: Solve for x
    x = 82,337.44/385.74
  6. Step 6: Final answer
    x = 213.45

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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.