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Finding the Fourth Proportional to 658.40, 987.39 and 398.39

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Solution

The fourth proportional to 658.40, 987.39 and 398.39 is: 597.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    658.40 : 987.39 = 398.39 : x
  2. Step 2: Convert to fraction form
    658.40/987.39 = 398.39/x
  3. Step 3: Cross multiply
    658.40x = 987.39 × 398.39
  4. Step 4: Simplify right side
    658.40x = 393,361.37
  5. Step 5: Solve for x
    x = 393,361.37/658.40
  6. Step 6: Final answer
    x = 597.45

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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.