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Finding the Fourth Proportional to 138.72, 206.88 and 130.56

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Solution

The fourth proportional to 138.72, 206.88 and 130.56 is: 194.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.72 : 206.88 = 130.56 : x
  2. Step 2: Convert to fraction form
    138.72/206.88 = 130.56/x
  3. Step 3: Cross multiply
    138.72x = 206.88 × 130.56
  4. Step 4: Simplify right side
    138.72x = 27,010.25
  5. Step 5: Solve for x
    x = 27,010.25/138.72
  6. Step 6: Final answer
    x = 194.71

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.