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Finding the Fourth Proportional to 122.50, 169.08 and 81.12

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Solution

The fourth proportional to 122.50, 169.08 and 81.12 is: 111.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.50 : 169.08 = 81.12 : x
  2. Step 2: Convert to fraction form
    122.50/169.08 = 81.12/x
  3. Step 3: Cross multiply
    122.50x = 169.08 × 81.12
  4. Step 4: Simplify right side
    122.50x = 13,715.77
  5. Step 5: Solve for x
    x = 13,715.77/122.50
  6. Step 6: Final answer
    x = 111.97

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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.