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Finding the Fourth Proportional to 789.68, 1,089.64 and 494.80

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Solution

The fourth proportional to 789.68, 1,089.64 and 494.80 is: 682.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.68 : 1,089.64 = 494.80 : x
  2. Step 2: Convert to fraction form
    789.68/1,089.64 = 494.80/x
  3. Step 3: Cross multiply
    789.68x = 1,089.64 × 494.80
  4. Step 4: Simplify right side
    789.68x = 539,153.87
  5. Step 5: Solve for x
    x = 539,153.87/789.68
  6. Step 6: Final answer
    x = 682.75

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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.