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Finding the Fourth Proportional to 122.72, 169.11 and 89.91

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Solution

The fourth proportional to 122.72, 169.11 and 89.91 is: 123.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.72 : 169.11 = 89.91 : x
  2. Step 2: Convert to fraction form
    122.72/169.11 = 89.91/x
  3. Step 3: Cross multiply
    122.72x = 169.11 × 89.91
  4. Step 4: Simplify right side
    122.72x = 15,204.68
  5. Step 5: Solve for x
    x = 15,204.68/122.72
  6. Step 6: Final answer
    x = 123.90

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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.