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Finding the Fourth Proportional to 685.88, 1,029.16 and 320.70

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Solution

The fourth proportional to 685.88, 1,029.16 and 320.70 is: 481.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.88 : 1,029.16 = 320.70 : x
  2. Step 2: Convert to fraction form
    685.88/1,029.16 = 320.70/x
  3. Step 3: Cross multiply
    685.88x = 1,029.16 × 320.70
  4. Step 4: Simplify right side
    685.88x = 330,048.15
  5. Step 5: Solve for x
    x = 330,048.15/685.88
  6. Step 6: Final answer
    x = 481.20

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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.