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Finding the Fourth Proportional to 122.10, 168.41 and 78.45

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Solution

The fourth proportional to 122.10, 168.41 and 78.45 is: 108.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.10 : 168.41 = 78.45 : x
  2. Step 2: Convert to fraction form
    122.10/168.41 = 78.45/x
  3. Step 3: Cross multiply
    122.10x = 168.41 × 78.45
  4. Step 4: Simplify right side
    122.10x = 13,211.96
  5. Step 5: Solve for x
    x = 13,211.96/122.10
  6. Step 6: Final answer
    x = 108.21

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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.