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Finding the Fourth Proportional to 686.22, 1,028.35 and 393.28

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Solution

The fourth proportional to 686.22, 1,028.35 and 393.28 is: 589.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.22 : 1,028.35 = 393.28 : x
  2. Step 2: Convert to fraction form
    686.22/1,028.35 = 393.28/x
  3. Step 3: Cross multiply
    686.22x = 1,028.35 × 393.28
  4. Step 4: Simplify right side
    686.22x = 404,429.49
  5. Step 5: Solve for x
    x = 404,429.49/686.22
  6. Step 6: Final answer
    x = 589.36

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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.