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Finding the Fourth Proportional to 258.86, 388.29 and 128.93

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Solution

The fourth proportional to 258.86, 388.29 and 128.93 is: 193.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.86 : 388.29 = 128.93 : x
  2. Step 2: Convert to fraction form
    258.86/388.29 = 128.93/x
  3. Step 3: Cross multiply
    258.86x = 388.29 × 128.93
  4. Step 4: Simplify right side
    258.86x = 50,060.77
  5. Step 5: Solve for x
    x = 50,060.77/258.86
  6. Step 6: Final answer
    x = 193.39

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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.