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Finding the Fourth Proportional to 398.72, 598.14 and 138.64

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Solution

The fourth proportional to 398.72, 598.14 and 138.64 is: 207.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.72 : 598.14 = 138.64 : x
  2. Step 2: Convert to fraction form
    398.72/598.14 = 138.64/x
  3. Step 3: Cross multiply
    398.72x = 598.14 × 138.64
  4. Step 4: Simplify right side
    398.72x = 82,926.13
  5. Step 5: Solve for x
    x = 82,926.13/398.72
  6. Step 6: Final answer
    x = 207.98

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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.