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Finding the Fourth Proportional to 91.89, 138.42 and 83.88

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Solution

The fourth proportional to 91.89, 138.42 and 83.88 is: 126.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.89 : 138.42 = 83.88 : x
  2. Step 2: Convert to fraction form
    91.89/138.42 = 83.88/x
  3. Step 3: Cross multiply
    91.89x = 138.42 × 83.88
  4. Step 4: Simplify right side
    91.89x = 11,610.67
  5. Step 5: Solve for x
    x = 11,610.67/91.89
  6. Step 6: Final answer
    x = 126.35

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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.