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Finding the Fourth Proportional to 685.60, 1,028.79 and 412.36

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Solution

The fourth proportional to 685.60, 1,028.79 and 412.36 is: 618.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.60 : 1,028.79 = 412.36 : x
  2. Step 2: Convert to fraction form
    685.60/1,028.79 = 412.36/x
  3. Step 3: Cross multiply
    685.60x = 1,028.79 × 412.36
  4. Step 4: Simplify right side
    685.60x = 424,231.84
  5. Step 5: Solve for x
    x = 424,231.84/685.60
  6. Step 6: Final answer
    x = 618.77

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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.