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Finding the Fourth Proportional to 136.98, 189.02 and 81.72

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Solution

The fourth proportional to 136.98, 189.02 and 81.72 is: 112.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.98 : 189.02 = 81.72 : x
  2. Step 2: Convert to fraction form
    136.98/189.02 = 81.72/x
  3. Step 3: Cross multiply
    136.98x = 189.02 × 81.72
  4. Step 4: Simplify right side
    136.98x = 15,446.31
  5. Step 5: Solve for x
    x = 15,446.31/136.98
  6. Step 6: Final answer
    x = 112.76

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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.