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Finding the Fourth Proportional to 123.91, 171.12 and 99.49

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Solution

The fourth proportional to 123.91, 171.12 and 99.49 is: 137.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.91 : 171.12 = 99.49 : x
  2. Step 2: Convert to fraction form
    123.91/171.12 = 99.49/x
  3. Step 3: Cross multiply
    123.91x = 171.12 × 99.49
  4. Step 4: Simplify right side
    123.91x = 17,024.73
  5. Step 5: Solve for x
    x = 17,024.73/123.91
  6. Step 6: Final answer
    x = 137.40

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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.