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Finding the Fourth Proportional to 257.12, 385.08 and 126.72

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Solution

The fourth proportional to 257.12, 385.08 and 126.72 is: 189.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.12 : 385.08 = 126.72 : x
  2. Step 2: Convert to fraction form
    257.12/385.08 = 126.72/x
  3. Step 3: Cross multiply
    257.12x = 385.08 × 126.72
  4. Step 4: Simplify right side
    257.12x = 48,797.34
  5. Step 5: Solve for x
    x = 48,797.34/257.12
  6. Step 6: Final answer
    x = 189.78

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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.