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Finding the Fourth Proportional to 386.28, 579.36 and 129.76

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Solution

The fourth proportional to 386.28, 579.36 and 129.76 is: 194.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.28 : 579.36 = 129.76 : x
  2. Step 2: Convert to fraction form
    386.28/579.36 = 129.76/x
  3. Step 3: Cross multiply
    386.28x = 579.36 × 129.76
  4. Step 4: Simplify right side
    386.28x = 75,177.75
  5. Step 5: Solve for x
    x = 75,177.75/386.28
  6. Step 6: Final answer
    x = 194.62

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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.