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Finding the Fourth Proportional to 398.12, 551.63 and 389.48

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Solution

The fourth proportional to 398.12, 551.63 and 389.48 is: 539.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.12 : 551.63 = 389.48 : x
  2. Step 2: Convert to fraction form
    398.12/551.63 = 389.48/x
  3. Step 3: Cross multiply
    398.12x = 551.63 × 389.48
  4. Step 4: Simplify right side
    398.12x = 214,848.85
  5. Step 5: Solve for x
    x = 214,848.85/398.12
  6. Step 6: Final answer
    x = 539.66

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.