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Finding the Fourth Proportional to 686.28, 1,028.88 and 320.88

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Solution

The fourth proportional to 686.28, 1,028.88 and 320.88 is: 481.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.28 : 1,028.88 = 320.88 : x
  2. Step 2: Convert to fraction form
    686.28/1,028.88 = 320.88/x
  3. Step 3: Cross multiply
    686.28x = 1,028.88 × 320.88
  4. Step 4: Simplify right side
    686.28x = 330,147.01
  5. Step 5: Solve for x
    x = 330,147.01/686.28
  6. Step 6: Final answer
    x = 481.07

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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.