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Finding the Fourth Proportional to 385.12, 578.69 and 211.91

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Solution

The fourth proportional to 385.12, 578.69 and 211.91 is: 318.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.12 : 578.69 = 211.91 : x
  2. Step 2: Convert to fraction form
    385.12/578.69 = 211.91/x
  3. Step 3: Cross multiply
    385.12x = 578.69 × 211.91
  4. Step 4: Simplify right side
    385.12x = 122,629.14
  5. Step 5: Solve for x
    x = 122,629.14/385.12
  6. Step 6: Final answer
    x = 318.42

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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.