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Finding the Fourth Proportional to 687.33, 1,031.31 and 427.74

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Solution

The fourth proportional to 687.33, 1,031.31 and 427.74 is: 641.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.33 : 1,031.31 = 427.74 : x
  2. Step 2: Convert to fraction form
    687.33/1,031.31 = 427.74/x
  3. Step 3: Cross multiply
    687.33x = 1,031.31 × 427.74
  4. Step 4: Simplify right side
    687.33x = 441,132.54
  5. Step 5: Solve for x
    x = 441,132.54/687.33
  6. Step 6: Final answer
    x = 641.81

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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.