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Finding the Fourth Proportional to 91.68, 137.67 and 81.42

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Solution

The fourth proportional to 91.68, 137.67 and 81.42 is: 122.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.68 : 137.67 = 81.42 : x
  2. Step 2: Convert to fraction form
    91.68/137.67 = 81.42/x
  3. Step 3: Cross multiply
    91.68x = 137.67 × 81.42
  4. Step 4: Simplify right side
    91.68x = 11,208.40
  5. Step 5: Solve for x
    x = 11,208.40/91.68
  6. Step 6: Final answer
    x = 122.26

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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.