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Finding the Fourth Proportional to 812, 1,120.74 and 517.20

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Solution

The fourth proportional to 812, 1,120.74 and 517.20 is: 713.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    812 : 1,120.74 = 517.20 : x
  2. Step 2: Convert to fraction form
    812/1,120.74 = 517.20/x
  3. Step 3: Cross multiply
    812x = 1,120.74 × 517.20
  4. Step 4: Simplify right side
    812x = 579,644.14
  5. Step 5: Solve for x
    x = 579,644.14/812
  6. Step 6: Final answer
    x = 713.85

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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.