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Finding the Fourth Proportional to 259.25, 388.78 and 129.21

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Solution

The fourth proportional to 259.25, 388.78 and 129.21 is: 193.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.25 : 388.78 = 129.21 : x
  2. Step 2: Convert to fraction form
    259.25/388.78 = 129.21/x
  3. Step 3: Cross multiply
    259.25x = 388.78 × 129.21
  4. Step 4: Simplify right side
    259.25x = 50,233.94
  5. Step 5: Solve for x
    x = 50,233.94/259.25
  6. Step 6: Final answer
    x = 193.76

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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.