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Finding the Fourth Proportional to 258.68, 387.70 and 136.86

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Solution

The fourth proportional to 258.68, 387.70 and 136.86 is: 205.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.68 : 387.70 = 136.86 : x
  2. Step 2: Convert to fraction form
    258.68/387.70 = 136.86/x
  3. Step 3: Cross multiply
    258.68x = 387.70 × 136.86
  4. Step 4: Simplify right side
    258.68x = 53,059.94
  5. Step 5: Solve for x
    x = 53,059.94/258.68
  6. Step 6: Final answer
    x = 205.12

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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.