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Finding the Fourth Proportional to 687.44, 1,031.16 and 379.28

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Solution

The fourth proportional to 687.44, 1,031.16 and 379.28 is: 568.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.44 : 1,031.16 = 379.28 : x
  2. Step 2: Convert to fraction form
    687.44/1,031.16 = 379.28/x
  3. Step 3: Cross multiply
    687.44x = 1,031.16 × 379.28
  4. Step 4: Simplify right side
    687.44x = 391,098.36
  5. Step 5: Solve for x
    x = 391,098.36/687.44
  6. Step 6: Final answer
    x = 568.92

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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.