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Finding the Fourth Proportional to 639.20, 879.98 and 573.59

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Solution

The fourth proportional to 639.20, 879.98 and 573.59 is: 789.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.20 : 879.98 = 573.59 : x
  2. Step 2: Convert to fraction form
    639.20/879.98 = 573.59/x
  3. Step 3: Cross multiply
    639.20x = 879.98 × 573.59
  4. Step 4: Simplify right side
    639.20x = 504,740.46
  5. Step 5: Solve for x
    x = 504,740.46/639.20
  6. Step 6: Final answer
    x = 789.65

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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.