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Finding the Fourth Proportional to 685.54, 1,028.28 and 320.20

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Solution

The fourth proportional to 685.54, 1,028.28 and 320.20 is: 480.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.54 : 1,028.28 = 320.20 : x
  2. Step 2: Convert to fraction form
    685.54/1,028.28 = 320.20/x
  3. Step 3: Cross multiply
    685.54x = 1,028.28 × 320.20
  4. Step 4: Simplify right side
    685.54x = 329,255.26
  5. Step 5: Solve for x
    x = 329,255.26/685.54
  6. Step 6: Final answer
    x = 480.29

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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.