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Finding the Fourth Proportional to 122.60, 169.20 and 78.35

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Solution

The fourth proportional to 122.60, 169.20 and 78.35 is: 108.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.60 : 169.20 = 78.35 : x
  2. Step 2: Convert to fraction form
    122.60/169.20 = 78.35/x
  3. Step 3: Cross multiply
    122.60x = 169.20 × 78.35
  4. Step 4: Simplify right side
    122.60x = 13,255.97
  5. Step 5: Solve for x
    x = 13,255.97/122.60
  6. Step 6: Final answer
    x = 108.13

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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.