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Finding the Fourth Proportional to 680.61, 1,020.21 and 387.48

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Solution

The fourth proportional to 680.61, 1,020.21 and 387.48 is: 580.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.61 : 1,020.21 = 387.48 : x
  2. Step 2: Convert to fraction form
    680.61/1,020.21 = 387.48/x
  3. Step 3: Cross multiply
    680.61x = 1,020.21 × 387.48
  4. Step 4: Simplify right side
    680.61x = 395,309.52
  5. Step 5: Solve for x
    x = 395,309.52/680.61
  6. Step 6: Final answer
    x = 580.82

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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.