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Finding the Fourth Proportional to 393.38, 589.95 and 129.78

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Solution

The fourth proportional to 393.38, 589.95 and 129.78 is: 194.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.38 : 589.95 = 129.78 : x
  2. Step 2: Convert to fraction form
    393.38/589.95 = 129.78/x
  3. Step 3: Cross multiply
    393.38x = 589.95 × 129.78
  4. Step 4: Simplify right side
    393.38x = 76,563.96
  5. Step 5: Solve for x
    x = 76,563.96/393.38
  6. Step 6: Final answer
    x = 194.63

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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.