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Finding the Fourth Proportional to 257.28, 385.99 and 92.80

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Solution

The fourth proportional to 257.28, 385.99 and 92.80 is: 139.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 385.99 = 92.80 : x
  2. Step 2: Convert to fraction form
    257.28/385.99 = 92.80/x
  3. Step 3: Cross multiply
    257.28x = 385.99 × 92.80
  4. Step 4: Simplify right side
    257.28x = 35,818.21
  5. Step 5: Solve for x
    x = 35,818.21/257.28
  6. Step 6: Final answer
    x = 139.22

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.