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Finding the Fourth Proportional to 138.42, 207.68 and 61.43

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Solution

The fourth proportional to 138.42, 207.68 and 61.43 is: 92.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.42 : 207.68 = 61.43 : x
  2. Step 2: Convert to fraction form
    138.42/207.68 = 61.43/x
  3. Step 3: Cross multiply
    138.42x = 207.68 × 61.43
  4. Step 4: Simplify right side
    138.42x = 12,756.44
  5. Step 5: Solve for x
    x = 12,756.44/138.42
  6. Step 6: Final answer
    x = 92.16

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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.