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Finding the Fourth Proportional to 789.75, 1,089.90 and 479.25

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Solution

The fourth proportional to 789.75, 1,089.90 and 479.25 is: 661.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.75 : 1,089.90 = 479.25 : x
  2. Step 2: Convert to fraction form
    789.75/1,089.90 = 479.25/x
  3. Step 3: Cross multiply
    789.75x = 1,089.90 × 479.25
  4. Step 4: Simplify right side
    789.75x = 522,334.58
  5. Step 5: Solve for x
    x = 522,334.58/789.75
  6. Step 6: Final answer
    x = 661.39

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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.