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Finding the Fourth Proportional to 257.43, 386.15 and 74.85

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Solution

The fourth proportional to 257.43, 386.15 and 74.85 is: 112.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.43 : 386.15 = 74.85 : x
  2. Step 2: Convert to fraction form
    257.43/386.15 = 74.85/x
  3. Step 3: Cross multiply
    257.43x = 386.15 × 74.85
  4. Step 4: Simplify right side
    257.43x = 28,902.95
  5. Step 5: Solve for x
    x = 28,902.95/257.43
  6. Step 6: Final answer
    x = 112.28

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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.