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Finding the Fourth Proportional to 171.92, 257.78 and 90.84

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Solution

The fourth proportional to 171.92, 257.78 and 90.84 is: 136.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.92 : 257.78 = 90.84 : x
  2. Step 2: Convert to fraction form
    171.92/257.78 = 90.84/x
  3. Step 3: Cross multiply
    171.92x = 257.78 × 90.84
  4. Step 4: Simplify right side
    171.92x = 23,416.74
  5. Step 5: Solve for x
    x = 23,416.74/171.92
  6. Step 6: Final answer
    x = 136.21

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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.