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Finding the Fourth Proportional to 171.88, 258 and 128.42

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Solution

The fourth proportional to 171.88, 258 and 128.42 is: 192.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.88 : 258 = 128.42 : x
  2. Step 2: Convert to fraction form
    171.88/258 = 128.42/x
  3. Step 3: Cross multiply
    171.88x = 258 × 128.42
  4. Step 4: Simplify right side
    171.88x = 33,132.36
  5. Step 5: Solve for x
    x = 33,132.36/171.88
  6. Step 6: Final answer
    x = 192.76

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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.