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Finding the Fourth Proportional to 398.61, 548.78 and 378.09

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Solution

The fourth proportional to 398.61, 548.78 and 378.09 is: 520.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.61 : 548.78 = 378.09 : x
  2. Step 2: Convert to fraction form
    398.61/548.78 = 378.09/x
  3. Step 3: Cross multiply
    398.61x = 548.78 × 378.09
  4. Step 4: Simplify right side
    398.61x = 207,486.34
  5. Step 5: Solve for x
    x = 207,486.34/398.61
  6. Step 6: Final answer
    x = 520.52

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.