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Finding the Fourth Proportional to 171.91, 257.98 and 90.81

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Solution

The fourth proportional to 171.91, 257.98 and 90.81 is: 136.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.91 : 257.98 = 90.81 : x
  2. Step 2: Convert to fraction form
    171.91/257.98 = 90.81/x
  3. Step 3: Cross multiply
    171.91x = 257.98 × 90.81
  4. Step 4: Simplify right side
    171.91x = 23,427.16
  5. Step 5: Solve for x
    x = 23,427.16/171.91
  6. Step 6: Final answer
    x = 136.28

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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.