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Finding the Fourth Proportional to 257.85, 386.99 and 142.38

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Solution

The fourth proportional to 257.85, 386.99 and 142.38 is: 213.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.85 : 386.99 = 142.38 : x
  2. Step 2: Convert to fraction form
    257.85/386.99 = 142.38/x
  3. Step 3: Cross multiply
    257.85x = 386.99 × 142.38
  4. Step 4: Simplify right side
    257.85x = 55,098.92
  5. Step 5: Solve for x
    x = 55,098.92/257.85
  6. Step 6: Final answer
    x = 213.69

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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.