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Finding the Fourth Proportional to 398.49, 595.20 and 387.55

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Solution

The fourth proportional to 398.49, 595.20 and 387.55 is: 578.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.49 : 595.20 = 387.55 : x
  2. Step 2: Convert to fraction form
    398.49/595.20 = 387.55/x
  3. Step 3: Cross multiply
    398.49x = 595.20 × 387.55
  4. Step 4: Simplify right side
    398.49x = 230,669.76
  5. Step 5: Solve for x
    x = 230,669.76/398.49
  6. Step 6: Final answer
    x = 578.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.