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Finding the Fourth Proportional to 687.90, 1,031.99 and 255.09

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Solution

The fourth proportional to 687.90, 1,031.99 and 255.09 is: 382.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.90 : 1,031.99 = 255.09 : x
  2. Step 2: Convert to fraction form
    687.90/1,031.99 = 255.09/x
  3. Step 3: Cross multiply
    687.90x = 1,031.99 × 255.09
  4. Step 4: Simplify right side
    687.90x = 263,250.33
  5. Step 5: Solve for x
    x = 263,250.33/687.90
  6. Step 6: Final answer
    x = 382.69

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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.