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Finding the Fourth Proportional to 789.71, 1,089.78 and 440.40

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Solution

The fourth proportional to 789.71, 1,089.78 and 440.40 is: 607.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.71 : 1,089.78 = 440.40 : x
  2. Step 2: Convert to fraction form
    789.71/1,089.78 = 440.40/x
  3. Step 3: Cross multiply
    789.71x = 1,089.78 × 440.40
  4. Step 4: Simplify right side
    789.71x = 479,939.11
  5. Step 5: Solve for x
    x = 479,939.11/789.71
  6. Step 6: Final answer
    x = 607.74

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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.