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Finding the Fourth Proportional to 91.92, 138.56 and 86.68

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Solution

The fourth proportional to 91.92, 138.56 and 86.68 is: 130.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.92 : 138.56 = 86.68 : x
  2. Step 2: Convert to fraction form
    91.92/138.56 = 86.68/x
  3. Step 3: Cross multiply
    91.92x = 138.56 × 86.68
  4. Step 4: Simplify right side
    91.92x = 12,010.38
  5. Step 5: Solve for x
    x = 12,010.38/91.92
  6. Step 6: Final answer
    x = 130.66

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.