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Finding the Fourth Proportional to 815.29, 1,221.31 and 712.69

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Solution

The fourth proportional to 815.29, 1,221.31 and 712.69 is: 1,067.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.29 : 1,221.31 = 712.69 : x
  2. Step 2: Convert to fraction form
    815.29/1,221.31 = 712.69/x
  3. Step 3: Cross multiply
    815.29x = 1,221.31 × 712.69
  4. Step 4: Simplify right side
    815.29x = 870,415.42
  5. Step 5: Solve for x
    x = 870,415.42/815.29
  6. Step 6: Final answer
    x = 1,067.61

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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.