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Finding the Fourth Proportional to 122.09, 168.40 and 98.80

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Solution

The fourth proportional to 122.09, 168.40 and 98.80 is: 136.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.09 : 168.40 = 98.80 : x
  2. Step 2: Convert to fraction form
    122.09/168.40 = 98.80/x
  3. Step 3: Cross multiply
    122.09x = 168.40 × 98.80
  4. Step 4: Simplify right side
    122.09x = 16,637.92
  5. Step 5: Solve for x
    x = 16,637.92/122.09
  6. Step 6: Final answer
    x = 136.28

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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.