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Finding the Fourth Proportional to 685.77, 1,028.40 and 425.39

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Solution

The fourth proportional to 685.77, 1,028.40 and 425.39 is: 637.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.77 : 1,028.40 = 425.39 : x
  2. Step 2: Convert to fraction form
    685.77/1,028.40 = 425.39/x
  3. Step 3: Cross multiply
    685.77x = 1,028.40 × 425.39
  4. Step 4: Simplify right side
    685.77x = 437,465.93
  5. Step 5: Solve for x
    x = 437,465.93/685.77
  6. Step 6: Final answer
    x = 637.92

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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.