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Finding the Fourth Proportional to 781.48, 1,078.37 and 449.89

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Solution

The fourth proportional to 781.48, 1,078.37 and 449.89 is: 620.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.48 : 1,078.37 = 449.89 : x
  2. Step 2: Convert to fraction form
    781.48/1,078.37 = 449.89/x
  3. Step 3: Cross multiply
    781.48x = 1,078.37 × 449.89
  4. Step 4: Simplify right side
    781.48x = 485,140.24
  5. Step 5: Solve for x
    x = 485,140.24/781.48
  6. Step 6: Final answer
    x = 620.80

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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.