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Finding the Fourth Proportional to 781.33, 1,078.05 and 449.69

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Solution

The fourth proportional to 781.33, 1,078.05 and 449.69 is: 620.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.33 : 1,078.05 = 449.69 : x
  2. Step 2: Convert to fraction form
    781.33/1,078.05 = 449.69/x
  3. Step 3: Cross multiply
    781.33x = 1,078.05 × 449.69
  4. Step 4: Simplify right side
    781.33x = 484,788.30
  5. Step 5: Solve for x
    x = 484,788.30/781.33
  6. Step 6: Final answer
    x = 620.47

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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.