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Finding the Fourth Proportional to 138.42, 207.68 and 74.25

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Solution

The fourth proportional to 138.42, 207.68 and 74.25 is: 111.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.42 : 207.68 = 74.25 : x
  2. Step 2: Convert to fraction form
    138.42/207.68 = 74.25/x
  3. Step 3: Cross multiply
    138.42x = 207.68 × 74.25
  4. Step 4: Simplify right side
    138.42x = 15,419.87
  5. Step 5: Solve for x
    x = 15,419.87/138.42
  6. Step 6: Final answer
    x = 111.40

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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.