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Finding the Fourth Proportional to 578.78, 868.21 and 213.59

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Solution

The fourth proportional to 578.78, 868.21 and 213.59 is: 320.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    578.78 : 868.21 = 213.59 : x
  2. Step 2: Convert to fraction form
    578.78/868.21 = 213.59/x
  3. Step 3: Cross multiply
    578.78x = 868.21 × 213.59
  4. Step 4: Simplify right side
    578.78x = 185,439.91
  5. Step 5: Solve for x
    x = 185,439.91/578.78
  6. Step 6: Final answer
    x = 320.40

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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.