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Finding the Fourth Proportional to 686.26, 1,028.63 and 320.75

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Solution

The fourth proportional to 686.26, 1,028.63 and 320.75 is: 480.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.26 : 1,028.63 = 320.75 : x
  2. Step 2: Convert to fraction form
    686.26/1,028.63 = 320.75/x
  3. Step 3: Cross multiply
    686.26x = 1,028.63 × 320.75
  4. Step 4: Simplify right side
    686.26x = 329,928.73
  5. Step 5: Solve for x
    x = 329,928.73/686.26
  6. Step 6: Final answer
    x = 480.77

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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.