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Finding the Fourth Proportional to 839.47, 1,257.85 and 513.85

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Solution

The fourth proportional to 839.47, 1,257.85 and 513.85 is: 769.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.47 : 1,257.85 = 513.85 : x
  2. Step 2: Convert to fraction form
    839.47/1,257.85 = 513.85/x
  3. Step 3: Cross multiply
    839.47x = 1,257.85 × 513.85
  4. Step 4: Simplify right side
    839.47x = 646,346.22
  5. Step 5: Solve for x
    x = 646,346.22/839.47
  6. Step 6: Final answer
    x = 769.95

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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.