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Finding the Fourth Proportional to 385.69, 578.49 and 142.15

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Solution

The fourth proportional to 385.69, 578.49 and 142.15 is: 213.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.69 : 578.49 = 142.15 : x
  2. Step 2: Convert to fraction form
    385.69/578.49 = 142.15/x
  3. Step 3: Cross multiply
    385.69x = 578.49 × 142.15
  4. Step 4: Simplify right side
    385.69x = 82,232.35
  5. Step 5: Solve for x
    x = 82,232.35/385.69
  6. Step 6: Final answer
    x = 213.21

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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.