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Finding the Fourth Proportional to 171.31, 256.91 and 99.61

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Solution

The fourth proportional to 171.31, 256.91 and 99.61 is: 149.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.31 : 256.91 = 99.61 : x
  2. Step 2: Convert to fraction form
    171.31/256.91 = 99.61/x
  3. Step 3: Cross multiply
    171.31x = 256.91 × 99.61
  4. Step 4: Simplify right side
    171.31x = 25,590.31
  5. Step 5: Solve for x
    x = 25,590.31/171.31
  6. Step 6: Final answer
    x = 149.38

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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.