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Finding the Fourth Proportional to 257.28, 386.91 and 205.34

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Solution

The fourth proportional to 257.28, 386.91 and 205.34 is: 308.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.28 : 386.91 = 205.34 : x
  2. Step 2: Convert to fraction form
    257.28/386.91 = 205.34/x
  3. Step 3: Cross multiply
    257.28x = 386.91 × 205.34
  4. Step 4: Simplify right side
    257.28x = 79,446.16
  5. Step 5: Solve for x
    x = 79,446.16/257.28
  6. Step 6: Final answer
    x = 308.79

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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.