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Finding the Fourth Proportional to 385.76, 578.64 and 142.31

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Solution

The fourth proportional to 385.76, 578.64 and 142.31 is: 213.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.76 : 578.64 = 142.31 : x
  2. Step 2: Convert to fraction form
    385.76/578.64 = 142.31/x
  3. Step 3: Cross multiply
    385.76x = 578.64 × 142.31
  4. Step 4: Simplify right side
    385.76x = 82,348.24
  5. Step 5: Solve for x
    x = 82,348.24/385.76
  6. Step 6: Final answer
    x = 213.47

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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.