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Finding the Fourth Proportional to 257.28, 385.76 and 112.80

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Solution

The fourth proportional to 257.28, 385.76 and 112.80 is: 169.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 385.76 = 112.80 : x
  2. Step 2: Convert to fraction form
    257.28/385.76 = 112.80/x
  3. Step 3: Cross multiply
    257.28x = 385.76 × 112.80
  4. Step 4: Simplify right side
    257.28x = 43,513.73
  5. Step 5: Solve for x
    x = 43,513.73/257.28
  6. Step 6: Final answer
    x = 169.13

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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.