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Finding the Fourth Proportional to 687.20, 1,031.25 and 254.34

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Solution

The fourth proportional to 687.20, 1,031.25 and 254.34 is: 381.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.20 : 1,031.25 = 254.34 : x
  2. Step 2: Convert to fraction form
    687.20/1,031.25 = 254.34/x
  3. Step 3: Cross multiply
    687.20x = 1,031.25 × 254.34
  4. Step 4: Simplify right side
    687.20x = 262,288.13
  5. Step 5: Solve for x
    x = 262,288.13/687.20
  6. Step 6: Final answer
    x = 381.68

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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.