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Finding the Fourth Proportional to 258.78, 388.17 and 76.18

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Solution

The fourth proportional to 258.78, 388.17 and 76.18 is: 114.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.78 : 388.17 = 76.18 : x
  2. Step 2: Convert to fraction form
    258.78/388.17 = 76.18/x
  3. Step 3: Cross multiply
    258.78x = 388.17 × 76.18
  4. Step 4: Simplify right side
    258.78x = 29,568.85
  5. Step 5: Solve for x
    x = 29,568.85/258.78
  6. Step 6: Final answer
    x = 114.26

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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.