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Finding the Fourth Proportional to 257.20, 385.80 and 185.20

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Solution

The fourth proportional to 257.20, 385.80 and 185.20 is: 277.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.20 : 385.80 = 185.20 : x
  2. Step 2: Convert to fraction form
    257.20/385.80 = 185.20/x
  3. Step 3: Cross multiply
    257.20x = 385.80 × 185.20
  4. Step 4: Simplify right side
    257.20x = 71,450.16
  5. Step 5: Solve for x
    x = 71,450.16/257.20
  6. Step 6: Final answer
    x = 277.80

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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.