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Finding the Fourth Proportional to 815.70, 1,126.09 and 628.78

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Solution

The fourth proportional to 815.70, 1,126.09 and 628.78 is: 868.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.70 : 1,126.09 = 628.78 : x
  2. Step 2: Convert to fraction form
    815.70/1,126.09 = 628.78/x
  3. Step 3: Cross multiply
    815.70x = 1,126.09 × 628.78
  4. Step 4: Simplify right side
    815.70x = 708,062.87
  5. Step 5: Solve for x
    x = 708,062.87/815.70
  6. Step 6: Final answer
    x = 868.04

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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.