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Finding the Fourth Proportional to 686.28, 1,029.28 and 199.20

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Solution

The fourth proportional to 686.28, 1,029.28 and 199.20 is: 298.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.28 : 1,029.28 = 199.20 : x
  2. Step 2: Convert to fraction form
    686.28/1,029.28 = 199.20/x
  3. Step 3: Cross multiply
    686.28x = 1,029.28 × 199.20
  4. Step 4: Simplify right side
    686.28x = 205,032.58
  5. Step 5: Solve for x
    x = 205,032.58/686.28
  6. Step 6: Final answer
    x = 298.76

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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.