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Finding the Fourth Proportional to 839.72, 1,257.90 and 656.20

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Solution

The fourth proportional to 839.72, 1,257.90 and 656.20 is: 982.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.72 : 1,257.90 = 656.20 : x
  2. Step 2: Convert to fraction form
    839.72/1,257.90 = 656.20/x
  3. Step 3: Cross multiply
    839.72x = 1,257.90 × 656.20
  4. Step 4: Simplify right side
    839.72x = 825,433.98
  5. Step 5: Solve for x
    x = 825,433.98/839.72
  6. Step 6: Final answer
    x = 982.99

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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.