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Finding the Fourth Proportional to 258.90, 388.30 and 76.30

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Solution

The fourth proportional to 258.90, 388.30 and 76.30 is: 114.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.90 : 388.30 = 76.30 : x
  2. Step 2: Convert to fraction form
    258.90/388.30 = 76.30/x
  3. Step 3: Cross multiply
    258.90x = 388.30 × 76.30
  4. Step 4: Simplify right side
    258.90x = 29,626.13
  5. Step 5: Solve for x
    x = 29,626.13/258.90
  6. Step 6: Final answer
    x = 114.43

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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.