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Finding the Fourth Proportional to 687.11, 1,031.11 and 641.54

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Solution

The fourth proportional to 687.11, 1,031.11 and 641.54 is: 962.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.11 : 1,031.11 = 641.54 : x
  2. Step 2: Convert to fraction form
    687.11/1,031.11 = 641.54/x
  3. Step 3: Cross multiply
    687.11x = 1,031.11 × 641.54
  4. Step 4: Simplify right side
    687.11x = 661,498.31
  5. Step 5: Solve for x
    x = 661,498.31/687.11
  6. Step 6: Final answer
    x = 962.73

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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.