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Finding the Fourth Proportional to 685.89, 1,029.29 and 320.72

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Solution

The fourth proportional to 685.89, 1,029.29 and 320.72 is: 481.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.89 : 1,029.29 = 320.72 : x
  2. Step 2: Convert to fraction form
    685.89/1,029.29 = 320.72/x
  3. Step 3: Cross multiply
    685.89x = 1,029.29 × 320.72
  4. Step 4: Simplify right side
    685.89x = 330,113.89
  5. Step 5: Solve for x
    x = 330,113.89/685.89
  6. Step 6: Final answer
    x = 481.29

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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.