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Finding the Fourth Proportional to 123.92, 171 and 74.78

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Solution

The fourth proportional to 123.92, 171 and 74.78 is: 103.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.92 : 171 = 74.78 : x
  2. Step 2: Convert to fraction form
    123.92/171 = 74.78/x
  3. Step 3: Cross multiply
    123.92x = 171 × 74.78
  4. Step 4: Simplify right side
    123.92x = 12,786.53
  5. Step 5: Solve for x
    x = 12,786.53/123.92
  6. Step 6: Final answer
    x = 103.19

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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.