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Finding the Fourth Proportional to 171.92, 257.45 and 90.79

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Solution

The fourth proportional to 171.92, 257.45 and 90.79 is: 135.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.92 : 257.45 = 90.79 : x
  2. Step 2: Convert to fraction form
    171.92/257.45 = 90.79/x
  3. Step 3: Cross multiply
    171.92x = 257.45 × 90.79
  4. Step 4: Simplify right side
    171.92x = 23,372.79
  5. Step 5: Solve for x
    x = 23,372.79/171.92
  6. Step 6: Final answer
    x = 135.95

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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.