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Finding the Fourth Proportional to 99.60, 137.42 and 81.29

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Solution

The fourth proportional to 99.60, 137.42 and 81.29 is: 112.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.60 : 137.42 = 81.29 : x
  2. Step 2: Convert to fraction form
    99.60/137.42 = 81.29/x
  3. Step 3: Cross multiply
    99.60x = 137.42 × 81.29
  4. Step 4: Simplify right side
    99.60x = 11,169.78
  5. Step 5: Solve for x
    x = 11,169.78/99.60
  6. Step 6: Final answer
    x = 112.15

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.