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Finding the Fourth Proportional to 258.55, 387.84 and 85.14

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Solution

The fourth proportional to 258.55, 387.84 and 85.14 is: 127.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.55 : 387.84 = 85.14 : x
  2. Step 2: Convert to fraction form
    258.55/387.84 = 85.14/x
  3. Step 3: Cross multiply
    258.55x = 387.84 × 85.14
  4. Step 4: Simplify right side
    258.55x = 33,020.70
  5. Step 5: Solve for x
    x = 33,020.70/258.55
  6. Step 6: Final answer
    x = 127.71

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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.