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Finding the Fourth Proportional to 687.43, 1,031.31 and 200.49

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Solution

The fourth proportional to 687.43, 1,031.31 and 200.49 is: 300.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.43 : 1,031.31 = 200.49 : x
  2. Step 2: Convert to fraction form
    687.43/1,031.31 = 200.49/x
  3. Step 3: Cross multiply
    687.43x = 1,031.31 × 200.49
  4. Step 4: Simplify right side
    687.43x = 206,767.34
  5. Step 5: Solve for x
    x = 206,767.34/687.43
  6. Step 6: Final answer
    x = 300.78

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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.