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Finding the Fourth Proportional to 257.28, 384.85 and 211.11

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Solution

The fourth proportional to 257.28, 384.85 and 211.11 is: 315.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 384.85 = 211.11 : x
  2. Step 2: Convert to fraction form
    257.28/384.85 = 211.11/x
  3. Step 3: Cross multiply
    257.28x = 384.85 × 211.11
  4. Step 4: Simplify right side
    257.28x = 81,244.50
  5. Step 5: Solve for x
    x = 81,244.50/257.28
  6. Step 6: Final answer
    x = 315.79

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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.