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Finding the Fourth Proportional to 685.22, 1,028.45 and 425.72

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Solution

The fourth proportional to 685.22, 1,028.45 and 425.72 is: 638.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.22 : 1,028.45 = 425.72 : x
  2. Step 2: Convert to fraction form
    685.22/1,028.45 = 425.72/x
  3. Step 3: Cross multiply
    685.22x = 1,028.45 × 425.72
  4. Step 4: Simplify right side
    685.22x = 437,824.46
  5. Step 5: Solve for x
    x = 437,824.46/685.22
  6. Step 6: Final answer
    x = 638.96

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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.