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Finding the Fourth Proportional to 122.58, 169.19 and 78.91

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Solution

The fourth proportional to 122.58, 169.19 and 78.91 is: 108.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.58 : 169.19 = 78.91 : x
  2. Step 2: Convert to fraction form
    122.58/169.19 = 78.91/x
  3. Step 3: Cross multiply
    122.58x = 169.19 × 78.91
  4. Step 4: Simplify right side
    122.58x = 13,350.78
  5. Step 5: Solve for x
    x = 13,350.78/122.58
  6. Step 6: Final answer
    x = 108.91

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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.