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Finding the Fourth Proportional to 680.72, 939.24 and 393.21

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Solution

The fourth proportional to 680.72, 939.24 and 393.21 is: 542.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.72 : 939.24 = 393.21 : x
  2. Step 2: Convert to fraction form
    680.72/939.24 = 393.21/x
  3. Step 3: Cross multiply
    680.72x = 939.24 × 393.21
  4. Step 4: Simplify right side
    680.72x = 369,318.56
  5. Step 5: Solve for x
    x = 369,318.56/680.72
  6. Step 6: Final answer
    x = 542.55

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.