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Finding the Fourth Proportional to 389.89, 580.73 and 381.78

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Solution

The fourth proportional to 389.89, 580.73 and 381.78 is: 568.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.89 : 580.73 = 381.78 : x
  2. Step 2: Convert to fraction form
    389.89/580.73 = 381.78/x
  3. Step 3: Cross multiply
    389.89x = 580.73 × 381.78
  4. Step 4: Simplify right side
    389.89x = 221,707.56
  5. Step 5: Solve for x
    x = 221,707.56/389.89
  6. Step 6: Final answer
    x = 568.64

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.