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Finding the Fourth Proportional to 122.78, 169.37 and 99.49

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Solution

The fourth proportional to 122.78, 169.37 and 99.49 is: 137.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.78 : 169.37 = 99.49 : x
  2. Step 2: Convert to fraction form
    122.78/169.37 = 99.49/x
  3. Step 3: Cross multiply
    122.78x = 169.37 × 99.49
  4. Step 4: Simplify right side
    122.78x = 16,849.70
  5. Step 5: Solve for x
    x = 16,849.70/122.78
  6. Step 6: Final answer
    x = 137.24

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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.