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Finding the Fourth Proportional to 812.12, 1,120.86 and 664.48

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Solution

The fourth proportional to 812.12, 1,120.86 and 664.48 is: 917.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.12 : 1,120.86 = 664.48 : x
  2. Step 2: Convert to fraction form
    812.12/1,120.86 = 664.48/x
  3. Step 3: Cross multiply
    812.12x = 1,120.86 × 664.48
  4. Step 4: Simplify right side
    812.12x = 744,789.05
  5. Step 5: Solve for x
    x = 744,789.05/812.12
  6. Step 6: Final answer
    x = 917.09

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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.