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Finding the Fourth Proportional to 123.78, 185.69 and 99.89

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Solution

The fourth proportional to 123.78, 185.69 and 99.89 is: 149.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.78 : 185.69 = 99.89 : x
  2. Step 2: Convert to fraction form
    123.78/185.69 = 99.89/x
  3. Step 3: Cross multiply
    123.78x = 185.69 × 99.89
  4. Step 4: Simplify right side
    123.78x = 18,548.57
  5. Step 5: Solve for x
    x = 18,548.57/123.78
  6. Step 6: Final answer
    x = 149.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.