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Finding the Fourth Proportional to 398.72, 597.65 and 138.65

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Solution

The fourth proportional to 398.72, 597.65 and 138.65 is: 207.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.72 : 597.65 = 138.65 : x
  2. Step 2: Convert to fraction form
    398.72/597.65 = 138.65/x
  3. Step 3: Cross multiply
    398.72x = 597.65 × 138.65
  4. Step 4: Simplify right side
    398.72x = 82,860.49
  5. Step 5: Solve for x
    x = 82,860.49/398.72
  6. Step 6: Final answer
    x = 207.81

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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.