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Finding the Fourth Proportional to 385.47, 578.21 and 212.26

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Solution

The fourth proportional to 385.47, 578.21 and 212.26 is: 318.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.47 : 578.21 = 212.26 : x
  2. Step 2: Convert to fraction form
    385.47/578.21 = 212.26/x
  3. Step 3: Cross multiply
    385.47x = 578.21 × 212.26
  4. Step 4: Simplify right side
    385.47x = 122,730.85
  5. Step 5: Solve for x
    x = 122,730.85/385.47
  6. Step 6: Final answer
    x = 318.39

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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.