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Finding the Fourth Proportional to 685.87, 1,028.31 and 320.46

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Solution

The fourth proportional to 685.87, 1,028.31 and 320.46 is: 480.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.87 : 1,028.31 = 320.46 : x
  2. Step 2: Convert to fraction form
    685.87/1,028.31 = 320.46/x
  3. Step 3: Cross multiply
    685.87x = 1,028.31 × 320.46
  4. Step 4: Simplify right side
    685.87x = 329,532.22
  5. Step 5: Solve for x
    x = 329,532.22/685.87
  6. Step 6: Final answer
    x = 480.46

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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.