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Finding the Fourth Proportional to 386.70, 580.05 and 257.55

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Solution

The fourth proportional to 386.70, 580.05 and 257.55 is: 386.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.70 : 580.05 = 257.55 : x
  2. Step 2: Convert to fraction form
    386.70/580.05 = 257.55/x
  3. Step 3: Cross multiply
    386.70x = 580.05 × 257.55
  4. Step 4: Simplify right side
    386.70x = 149,391.88
  5. Step 5: Solve for x
    x = 149,391.88/386.70
  6. Step 6: Final answer
    x = 386.33

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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.