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Finding the Fourth Proportional to 685.50, 945.68 and 489.12

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Solution

The fourth proportional to 685.50, 945.68 and 489.12 is: 674.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.50 : 945.68 = 489.12 : x
  2. Step 2: Convert to fraction form
    685.50/945.68 = 489.12/x
  3. Step 3: Cross multiply
    685.50x = 945.68 × 489.12
  4. Step 4: Simplify right side
    685.50x = 462,548.56
  5. Step 5: Solve for x
    x = 462,548.56/685.50
  6. Step 6: Final answer
    x = 674.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.