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Finding the Fourth Proportional to 123.05, 169.86 and 83.78

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Solution

The fourth proportional to 123.05, 169.86 and 83.78 is: 115.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.05 : 169.86 = 83.78 : x
  2. Step 2: Convert to fraction form
    123.05/169.86 = 83.78/x
  3. Step 3: Cross multiply
    123.05x = 169.86 × 83.78
  4. Step 4: Simplify right side
    123.05x = 14,230.87
  5. Step 5: Solve for x
    x = 14,230.87/123.05
  6. Step 6: Final answer
    x = 115.65

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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.