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Finding the Fourth Proportional to 122.40, 168.95 and 85.57

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Solution

The fourth proportional to 122.40, 168.95 and 85.57 is: 118.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.40 : 168.95 = 85.57 : x
  2. Step 2: Convert to fraction form
    122.40/168.95 = 85.57/x
  3. Step 3: Cross multiply
    122.40x = 168.95 × 85.57
  4. Step 4: Simplify right side
    122.40x = 14,456.36
  5. Step 5: Solve for x
    x = 14,456.36/122.40
  6. Step 6: Final answer
    x = 118.11

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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.