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Finding the Fourth Proportional to 685.28, 1,027.68 and 320.24

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Solution

The fourth proportional to 685.28, 1,027.68 and 320.24 is: 480.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.28 : 1,027.68 = 320.24 : x
  2. Step 2: Convert to fraction form
    685.28/1,027.68 = 320.24/x
  3. Step 3: Cross multiply
    685.28x = 1,027.68 × 320.24
  4. Step 4: Simplify right side
    685.28x = 329,104.24
  5. Step 5: Solve for x
    x = 329,104.24/685.28
  6. Step 6: Final answer
    x = 480.25

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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.