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Finding the Fourth Proportional to 258.87, 387.90 and 186.78

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Solution

The fourth proportional to 258.87, 387.90 and 186.78 is: 279.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.87 : 387.90 = 186.78 : x
  2. Step 2: Convert to fraction form
    258.87/387.90 = 186.78/x
  3. Step 3: Cross multiply
    258.87x = 387.90 × 186.78
  4. Step 4: Simplify right side
    258.87x = 72,451.96
  5. Step 5: Solve for x
    x = 72,451.96/258.87
  6. Step 6: Final answer
    x = 279.88

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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.