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Finding the Fourth Proportional to 258.26, 387.48 and 128.25

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Solution

The fourth proportional to 258.26, 387.48 and 128.25 is: 192.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.26 : 387.48 = 128.25 : x
  2. Step 2: Convert to fraction form
    258.26/387.48 = 128.25/x
  3. Step 3: Cross multiply
    258.26x = 387.48 × 128.25
  4. Step 4: Simplify right side
    258.26x = 49,694.31
  5. Step 5: Solve for x
    x = 49,694.31/258.26
  6. Step 6: Final answer
    x = 192.42

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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.